Swaledale, IA Natural Disasters and Weather Extremes
Hot Rankings
The chance of earthquake damage in Swaledale is about the same as Iowa average and is much lower than the national average. The risk of tornado damage in Swaledale is about the same as Iowa average and is much higher than the national average.
Earthquake Index, #492
| Swaledale, IA | 0.00 |
| Iowa | 0.00 |
| U.S. | 1.81 |
The earthquake index value is calculated based on historical earthquake events data using USA.com algorithms. It is an indicator of the earthquake level in a region. A higher earthquake index value means a higher chance of an earthquake.
Volcano Index, #1
| Swaledale, IA | 0.0000 |
| Iowa | 0.0000 |
| U.S. | 0.0023 |
The volcano index value is calculated based on the currently known volcanoes using USA.com algorithms. It is an indicator of the possibility of a region being affected by a possible volcano eruption. A higher volcano index value means a higher chance of being affected.
Tornado Index, #519
| Swaledale, IA | 232.49 |
| Iowa | 236.74 |
| U.S. | 136.45 |
The tornado index value is calculated based on historical tornado events data using USA.com algorithms. It is an indicator of the tornado level in a region. A higher tornado index value means a higher chance of tornado events.
Other Weather Extremes Events
A total of 3,340 other weather extremes events within 50 miles of Swaledale, IA were recorded from 1950 to 2010. The following is a break down of these events:
| Type | Count | Type | Count | Type | Count | Type | Count | Type | Count |
| Avalanche: | 0 | Blizzard: | 39 | Cold: | 30 | Dense Fog: | 4 | Drought: | 9 |
| Dust Storm: | 0 | Flood: | 398 | Hail: | 1,209 | Heat: | 9 | Heavy Snow: | 42 |
| High Surf: | 0 | Hurricane: | 0 | Ice Storm: | 27 | Landslide: | 0 | Strong Wind: | 75 |
| Thunderstorm Winds: | 1,180 | Tropical Storm: | 0 | Wildfire: | 0 | Winter Storm: | 73 | Winter Weather: | 31 |
| Other: | 214 | ||||||||
Volcanos Nearby
No volcano is found in or near Swaledale, IA.
Historical Earthquake Events
No historical earthquake events that had recorded magnitudes of 3.5 or above found in or near Swaledale, IA.
No historical earthquake events found in or near Swaledale, IA.
Historical Tornado Events
A total of 94 historical tornado events that had recorded magnitude of 2 or above found in or near Swaledale, IA.
| Distance (miles) | Date | Magnitude | Start Lat/Log | End Lat/Log | Length | Width | Fatalities | Injuries | Property Damage | Crop Damage | Affected County |
| 5.8 | 1998-06-27 | 2 | 42°59'N / 93°26'W | 43°04'N / 93°23'W | 7.50 Miles | 50 Yards | 0 | 0 | 50K | 2K | Cerro Gordo |
| Brief Description: Iowa was located in the warm sector of a developing storm system to the west. The warm front had moved to the northern Iowa border during the afternoon of the 27th with dew point temperatures in the mid 70s to around 80 blanketing the state in the warm sector. Initially, the airmass was capped, preventing thunderstorms from forming during the afternoon. Slightly cooler air moved in during the evening hours. In addition to the slightly cooler air moving in aloft, a cold front was poised over eastern Nebraska ready to move east into the state. Thunderstorms erupted rapidly by early evening with hail and high winds reported over northern Iowa. There were numerous reports of hail of an inch or larger in diameter, with a few reports of golf ball size hail. High winds were also a problem with many of the storms producing 60 to 70 MPH wind gusts. Reports of tree and power line damage were widespread. There were a few tornadoes as well. One tracked across open country in Cerro Gordo County before damaging a house south of Clear Lake. Another tornado touched down near Swaledale in Cerro Gordo County and passed southeast of Mason City. Much of the track was over open country, however one house was destroyed near Swaledale by this tornado. The longest track tornado moved across Butler and Bremer Counties. It also passed through open country, causing damage to crops and out buildings. In addition to these, there were a few brief touchdowns reported. Iowa soil remained very saturated with numerous rivers at or near flood stage. Heavy rainfall of near 4 inches in a couple hours time caused flash flooding in Cerro Gordo County. A widespread area of north central into northeast Iowa received heavy rainfall. Many areas picked up two to four inches of rain in a few hour period. This resulted in urban and small stream flooding, and ultimately general river flooding in the days that followed. As the storms moved through Worth County, lightning struck an outbuilding west of Kensett. The building was set on fire and destroyed. | |||||||||||
| 6.4 | 1998-06-27 | 2 | 42°59'N / 93°20'W | 43°04'N / 93°05'W | 12.50 Miles | 50 Yards | 0 | 0 | 125K | 10K | Cerro Gordo |
| Brief Description: Iowa was located in the warm sector of a developing storm system to the west. The warm front had moved to the northern Iowa border during the afternoon of the 27th with dew point temperatures in the mid 70s to around 80 blanketing the state in the warm sector. Initially, the airmass was capped, preventing thunderstorms from forming during the afternoon. Slightly cooler air moved in during the evening hours. In addition to the slightly cooler air moving in aloft, a cold front was poised over eastern Nebraska ready to move east into the state. Thunderstorms erupted rapidly by early evening with hail and high winds reported over northern Iowa. There were numerous reports of hail of an inch or larger in diameter, with a few reports of golf ball size hail. High winds were also a problem with many of the storms producing 60 to 70 MPH wind gusts. Reports of tree and power line damage were widespread. There were a few tornadoes as well. One tracked across open country in Cerro Gordo County before damaging a house south of Clear Lake. Another tornado touched down near Swaledale in Cerro Gordo County and passed southeast of Mason City. Much of the track was over open country, however one house was destroyed near Swaledale by this tornado. The longest track tornado moved across Butler and Bremer Counties. It also passed through open country, causing damage to crops and out buildings. In addition to these, there were a few brief touchdowns reported. Iowa soil remained very saturated with numerous rivers at or near flood stage. Heavy rainfall of near 4 inches in a couple hours time caused flash flooding in Cerro Gordo County. A widespread area of north central into northeast Iowa received heavy rainfall. Many areas picked up two to four inches of rain in a few hour period. This resulted in urban and small stream flooding, and ultimately general river flooding in the days that followed. As the storms moved through Worth County, lightning struck an outbuilding west of Kensett. The building was set on fire and destroyed. | |||||||||||
| 8.5 | 1973-09-26 | 2 | 42°58'N / 93°29'W | 2.00 Miles | 100 Yards | 0 | 0 | 25K | 0 | Cerro Gordo | |
| 11.6 | 1967-04-30 | 3 | 43°06'N / 93°25'W | 43°11'N / 93°18'W | 7.70 Miles | 250 Yards | 0 | 0 | 250K | 0 | Cerro Gordo |
| 13.4 | 1959-05-10 | 2 | 42°45'N / 93°20'W | 42°49'N / 93°14'W | 6.50 Miles | 300 Yards | 0 | 0 | 25K | 0 | Franklin |
| 13.7 | 1953-05-10 | 4 | 43°04'N / 93°31'W | 43°10'N / 93°30'W | 6.40 Miles | 33 Yards | 0 | 3 | 250K | 0 | Hancock |
| 13.8 | 1973-09-26 | 2 | 43°01'N / 93°35'W | 1.00 Mile | 50 Yards | 0 | 0 | 25K | 0 | Hancock | |
| 15.4 | 1980-05-29 | 2 | 43°11'N / 93°12'W | 0.50 Mile | 30 Yards | 0 | 0 | 25K | 0 | Cerro Gordo | |
| 16.2 | 1966-10-14 | 5 | 42°48'N / 93°39'W | 42°55'N / 93°32'W | 9.70 Miles | 1000 Yards | 6 | 172 | 25.0M | 0 | Wright |
| 18.8 | 1968-05-15 | 5 | 42°46'N / 93°07'W | 42°54'N / 92°53'W | 14.70 Miles | 600 Yards | 0 | 0 | 0K | 0 | Franklin |
| 23.1 | 1964-08-29 | 2 | 43°18'N / 93°26'W | 2.00 Miles | 100 Yards | 0 | 0 | 25K | 0 | Worth | |
| 23.6 | 1952-05-23 | 2 | 42°45'N / 92°58'W | 0 | 0 | 0K | 0 | Butler | |||
| 23.8 | 1953-05-10 | 4 | 43°10'N / 93°30'W | 43°27'N / 93°23'W | 20.20 Miles | 33 Yards | 0 | 0 | 250K | 0 | Cerro Gordo |
| 25.0 | 1980-09-20 | 2 | 42°56'N / 94°00'W | 42°58'N / 93°37'W | 19.30 Miles | 33 Yards | 0 | 0 | 2.5M | 0 | Hancock |
| 26.7 | 1974-05-28 | 3 | 43°20'N / 93°13'W | 43°22'N / 93°08'W | 3.80 Miles | 150 Yards | 0 | 3 | 2.5M | 0 | Worth |
| 26.9 | 1973-09-26 | 2 | 42°49'N / 93°48'W | 1.00 Mile | 100 Yards | 0 | 0 | 25K | 0 | Wright | |
| 27.6 | 1970-09-09 | 2 | 42°54'N / 92°48'W | 42°56'N / 92°45'W | 1.90 Miles | 200 Yards | 0 | 0 | 25K | 0 | Butler |
| 27.8 | 1967-04-30 | 2 | 43°13'N / 93°48'W | 43°14'N / 93°42'W | 4.30 Miles | 300 Yards | 0 | 0 | 2.5M | 0 | Hancock |
| 28.6 | 1990-06-28 | 3 | 42°38'N / 93°10'W | 42°33'N / 93°03'W | 7.00 Miles | 90 Yards | 0 | 0 | 2.5M | 0 | Franklin |
| 28.9 | 1971-06-06 | 2 | 42°52'N / 92°47'W | 42°54'N / 92°44'W | 1.30 Miles | 200 Yards | 0 | 1 | 250K | 0 | Greene |
| 29.1 | 1990-08-02 | 2 | 43°16'N / 93°49'W | 43°16'N / 93°39'W | 7.00 Miles | 63 Yards | 0 | 0 | 250K | 0 | Winnebago |
| 29.3 | 1961-09-01 | 4 | 42°47'N / 93°00'W | 42°52'N / 92°33'W | 23.30 Miles | 27 Yards | 0 | 7 | 2.5M | 0 | Butler |
| 29.5 | 1951-06-25 | 2 | 43°13'N / 93°48'W | 0.80 Mile | 500 Yards | 0 | 8 | 0K | 0 | Hancock | |
| 29.7 | 1967-04-30 | 4 | 43°18'N / 93°10'W | 43°26'N / 92°58'W | 13.30 Miles | 400 Yards | 0 | 0 | 250K | 0 | Worth |
| 30.3 | 1980-09-20 | 2 | 43°19'N / 93°38'W | 43°26'N / 93°30'W | 10.20 Miles | 60 Yards | 0 | 0 | 2.5M | 0 | Winnebago |
| 30.5 | 1968-05-15 | 5 | 42°54'N / 92°53'W | 43°10'N / 92°33'W | 24.70 Miles | 600 Yards | 13 | 450 | 25.0M | 0 | Floyd |
| 30.5 | 1982-05-17 | 2 | 43°13'N / 93°49'W | 43°15'N / 93°48'W | 2.00 Miles | 80 Yards | 0 | 0 | 250K | 0 | Hancock |
| 30.5 | 1963-05-09 | 2 | 43°13'N / 93°55'W | 43°17'N / 93°40'W | 13.10 Miles | 400 Yards | 0 | 0 | 250K | 0 | Hancock |
| 30.7 | 1953-05-20 | 3 | 42°33'N / 93°03'W | 43°12'N / 92°24'W | 55.60 Miles | 400 Yards | 0 | 0 | 0K | 0 | Hardin |
| 30.7 | 1981-05-23 | 2 | 43°16'N / 92°55'W | 43°18'N / 92°50'W | 3.80 Miles | 50 Yards | 0 | 0 | 250K | 0 | Mitchell |
| 30.9 | 1964-04-26 | 2 | 42°36'N / 93°44'W | 42°39'N / 93°39'W | 4.70 Miles | 300 Yards | 0 | 0 | 25K | 0 | Wright |
| 30.9 | 1984-06-07 | 2 | 43°12'N / 93°49'W | 43°17'N / 93°48'W | 5.00 Miles | 127 Yards | 0 | 0 | 2.5M | 0 | Hancock |
| 30.9 | 1999-08-09 | 2 | 43°24'N / 93°31'W | 43°24'N / 93°31'W | 3.50 Miles | 40 Yards | 0 | 0 | 50K | 5K | Worth |
| Brief Description: An unstable airmass was in place over Iowa during the afternoon and evening hours of the 9th. Satellite and sounding data suggested the atmosphere was capped at about 775 mb by a warm layer of air with temperatures as high as 18 C. or more. Thunderstorms had a hard time firing off. A cold front moved southeast into the state as rich low level air with dew point temperatures in the mid 70s preceded the front. While the front moved southeast, a speed max near 100 kts in strength moved into the north central U.S. This combined with an upper level short wave helped a few of the storms break the cap. The wind profile was favourable with a strong shearing environment. Thunderstorms moved into north central Iowa and became tornadic quickly. There was basically one cell that produced at least two tornadoes as it slipped southeast into Iowa. The first tornado touched down in Winnebago County near Scarville. The tornado moved southeast across the county and advanced into Worth County by a few miles. The tornado caused crop damage and some building damage along its path. The corner of a bank building was torn off in the town of Joice in Worth County for example. The same cell produced another brief tornado touchdown near Burchinal in Cerro Gordo County near the intersection of I-35 and County Highway B-43. No significant damage was reported with this tornado. As the large cell that produced the tornado moved on, the rear flank downdraft produced high winds once again in the Scarville area. Power lines were downed and a few buildings were damaged by the high winds in the town of Scarville. High winds also struck the airport in Mason City with a wind gust of 58 MPH. | |||||||||||
| 31.1 | 1964-08-29 | 2 | 43°22'N / 93°27'W | 43°29'N / 93°17'W | 11.20 Miles | 150 Yards | 0 | 0 | 25K | 0 | Worth |
| 31.3 | 1991-05-17 | 2 | 42°35'N / 93°41'W | 42°37'N / 93°38'W | 2.50 Miles | 60 Yards | 0 | 0 | 25K | 0 | Wright |
| 31.5 | 1975-06-04 | 2 | 42°51'N / 92°43'W | 0 | 0 | 25K | 0 | Butler | |||
| 32.2 | 1964-08-27 | 2 | 43°06'N / 92°42'W | 1.00 Mile | 77 Yards | 0 | 0 | 25K | 0 | Floyd | |
| 32.2 | 1971-05-31 | 2 | 42°33'N / 93°02'W | 42°36'N / 92°57'W | 4.50 Miles | 300 Yards | 0 | 0 | 250K | 0 | Hardin |
| 32.6 | 1984-06-07 | 2 | 42°53'N / 94°03'W | 43°00'N / 93°52'W | 14.00 Miles | 150 Yards | 0 | 0 | 2.5M | 0 | Hancock |
| 33.2 | 1980-09-20 | 2 | 43°26'N / 93°30'W | 43°27'N / 93°28'W | 0 | 0 | 2.5M | 0 | Worth | ||
| 33.3 | 1990-06-28 | 3 | 42°33'N / 93°03'W | 42°32'N / 93°01'W | 2.00 Miles | 90 Yards | 0 | 0 | 2.5M | 0 | Hardin |
| 33.3 | 1999-08-09 | 2 | 43°28'N / 93°37'W | 43°23'N / 93°30'W | 8.00 Miles | 40 Yards | 0 | 0 | 100K | 10K | Winnebago |
| Brief Description: An unstable airmass was in place over Iowa during the afternoon and evening hours of the 9th. Satellite and sounding data suggested the atmosphere was capped at about 775 mb by a warm layer of air with temperatures as high as 18 C. or more. Thunderstorms had a hard time firing off. A cold front moved southeast into the state as rich low level air with dew point temperatures in the mid 70s preceded the front. While the front moved southeast, a speed max near 100 kts in strength moved into the north central U.S. This combined with an upper level short wave helped a few of the storms break the cap. The wind profile was favourable with a strong shearing environment. Thunderstorms moved into north central Iowa and became tornadic quickly. There was basically one cell that produced at least two tornadoes as it slipped southeast into Iowa. The first tornado touched down in Winnebago County near Scarville. The tornado moved southeast across the county and advanced into Worth County by a few miles. The tornado caused crop damage and some building damage along its path. The corner of a bank building was torn off in the town of Joice in Worth County for example. The same cell produced another brief tornado touchdown near Burchinal in Cerro Gordo County near the intersection of I-35 and County Highway B-43. No significant damage was reported with this tornado. As the large cell that produced the tornado moved on, the rear flank downdraft produced high winds once again in the Scarville area. Power lines were downed and a few buildings were damaged by the high winds in the town of Scarville. High winds also struck the airport in Mason City with a wind gust of 58 MPH. | |||||||||||
| 33.5 | 1954-05-23 | 2 | 43°17'N / 92°48'W | 0 | 0 | 0K | 0 | Mitchell | |||
| 34.0 | 1967-04-30 | 3 | 43°20'N / 93°12'W | 43°34'N / 93°04'W | 17.20 Miles | 800 Yards | 0 | 0 | 2.5M | 0 | Worth |
| 34.6 | 1982-05-17 | 2 | 43°15'N / 93°48'W | 43°27'N / 93°45'W | 11.00 Miles | 80 Yards | 0 | 0 | 250K | 0 | Winnebago |
| 35.0 | 1966-06-11 | 2 | 43°23'N / 92°54'W | 1.00 Mile | 250 Yards | 0 | 0 | 25K | 0 | Mitchell | |
| 35.5 | 1953-06-07 | 2 | 42°28'N / 94°00'W | 42°52'N / 93°45'W | 30.20 Miles | 200 Yards | 0 | 0 | 0K | 0 | Webster |
| 35.5 | 1967-04-30 | 4 | 43°27'N / 93°10'W | 43°30'N / 93°07'W | 3.00 Miles | 500 Yards | 0 | 1 | 2.5M | 0 | Worth |
| 35.7 | 1971-07-12 | 3 | 43°20'N / 93°02'W | 43°28'N / 92°47'W | 15.40 Miles | 833 Yards | 0 | 0 | 2.5M | 0 | Worth |
| 36.1 | 1991-05-17 | 2 | 42°29'N / 93°42'W | 42°35'N / 93°41'W | 6.50 Miles | 60 Yards | 0 | 0 | 25K | 0 | Hamilton |
| 36.2 | 1974-06-09 | 2 | 43°05'N / 94°01'W | 0 | 0 | 250K | 0 | Kossuth | |||
| 36.2 | 1984-06-07 | 2 | 43°17'N / 93°48'W | 43°28'N / 93°46'W | 13.00 Miles | 127 Yards | 0 | 0 | 2.5M | 0 | Winnebago |
| 37.0 | 1965-05-05 | 4 | 43°17'N / 92°49'W | 43°23'N / 92°43'W | 8.20 Miles | 150 Yards | 0 | 6 | 25K | 0 | Floyd |
| 37.2 | 1986-09-28 | 2 | 43°09'N / 92°37'W | 0.20 Mile | 23 Yards | 0 | 2 | 250K | 0 | Floyd | |
| 37.5 | 2008-05-25 | 2 | 42°33'N / 92°52'W | 42°33'N / 92°51'W | 1.00 Mile | 75 Yards | 0 | 0 | 300K | 2K | Grundy |
| Brief Description: EVENT NARRATIVE: This was the initial tornado touchdown point. The tornado continued on into Butler County. EPISODE NARRATIVE: A very intense upper low was located over the southwest U.S. and lifted northeast during the weekend of the 24th into the morning of the 26th. The seasons first strong push of deep moisture moved into Iowa on the 25th with surface temperatures warming into the mid 80s and dew points surging into the upper 60s to low 70s. Precipitable water values were near 1.5 inches. The dry slot pushed north across the area the previous night as the warm front lifted north. The primary surface low was located over northern Minnesota. A cold front extended south from the low into northwest Iowa. The airmass became very unstable by the mid afternoon hours. MUCAPE rose to between 4000 and 5000 J/kg. Lifted indices fell to -8 to -11 C. There was a considerable amount of both DCAPE at 1000-1500 J/kg and cape in the -10 to-30 C. layer of the atmoshpere, between 400 and 600 J/kg. The freezing level was around 13,200 feet. The environment was quite sheared with effective shear in the 40 to 50 kt range. LCL values were between 1000 and 1500 meters. The airmass was initially capped. During the late afternoon hours, a small cluster of thunderstorms formed over north central into northeast Iowa. The storms became severe very quickly. Initially, the storms dropped hail up to golf ball in size. One became a strong super cell and produced a major tornado. This cell, in addition to being tornadic, also produced hail of baseball to softball in size and winds in excess of 90 MPH. The tornado track was from approximately 2 miles south of Aplington to Parkersburg, then continued to New Hartford and across northern Black Hawk County. The average path width ranged from 0.6 to 0.7 miles near Parkersburg to just north of New Hartford. The path constricted to near one quarter mile wide east of New Hartford to north of Waterloo. The width then increased to near 1.2 miles wide north of Dunkerton before dissipating near the Black Hawk and Buchanan County line. The tornado was on the ground for approximately 43 miles. In addition to the main tornado, a satellite tornado was observed by storm chasers and one off duty NWS employee. It was located south of the main tornado and was on the ground for a little over a mile in Grundy County. Initial reports indicated 9 fatalities with 7 in Parkersburg (pop 1889) and 2 in New Hartford (pop 637). There were at least 50 injuries, with 4 of those in critical condition. Two of the fatalities occurred a few days after the tornado from injuries sustained in the tornado. The last fatality occurred on 7 Nov. A 61 year old female sustained injuries in the stairwell of her home when a 2 x 4 was thrown through her right side lung. She was hospitalized and died several months later of complications. Significant structural damage occurred across the southern end of Parkersburg and along a path to just north of New Hartford. Numerous structures completely destroyed from Parkersburg to near New Hartford. The tornado continued eastward to just north of the Waterloo and Cedar Falls area. Significant damage also occurred north of Dunkerton where the tornado increased to its greatest path width. This storm also produced substantial straight line wind damage along the southern periphery of the storm just south of the tornado track. News accounts indicated that a receipt from Parkersburg was found around 1915 CST 3 miles north of Prairie du Chien, WI, 109 miles to the northeast. Receipits were also found in Clayton County at Elkader, and full scrapbook pages and photos were found in far northeast Bremer County at Sumner. Preliminary estimates that straight line winds of 90 to 100 MPH occurred with this storm. At 1637 CST, the Waterloo Airport recorded a 93 MPH wind gust. Survey results suggest that straight line wind damage was the cause of the severe damage at the recreational vehicle dealership north of Cedar Falls. At least 627 homes were damaged, including 288 homes destroyed in Parkersburg, 88 in New Hartford, 15 in Hazelton and another 50 in Black Hawk County. In addition, 58 had major damage, 33 had moderate damage, 2 were inaccessible, and 93 damaged but able to be occupied. There were also 21 businesses destroyed. Governor Chet Culver declared both Butler and Black Hawk disaster areas with both given the State Declaration. A Federal Disaster Declaration occurred two days later for both Butler and Black Hawk Counties. The tornado was rated a low end EF5 by a Quick Response Team (QRT) in portions of Parkersburg and north of New Hartford with peak winds estimated at 205 MPH. For historical reference, the last F5 tornado to hit Iowa was on 13 June 1976 in Boone and Story Counties in the town of Jordan, with a 21 mile path length. The last F4 tornado to hit Iowa was in Union, Madison, and Dallas Counties with a 56 mile path length on 8 April 1999. There was one other smaller tornado during the evening. A tornado touched down in Clarke County and was on the ground for a short time southeast of Osceola. After the initial thunderstorm area developed over north central and northeast Iowa, a large complex developed over southeast Nebraska. The two areas of storms filled in to form a squall line by the mid evening hours. The complex over Nebraska then pushed east and northeast along the squall line. A considerable amount of severe weather was generated during the evening as this occurred. Along the squall line, high winds and hail were common with the dominant mode of severe weather being hail of up to golf ball in size. As the MCS out of Nebraska advanced east, a tail extending south from the centroid took on a bow echo configuration and raced east across Iowa at 65 MPH. Very high winds occurred with this feature with numerous locations reporting winds of 65 to 85 MPH. Some of the higher winds included an 85 MPH wind gust in the Winterset area and numerous reports of 75 to 85 MPH winds from Madison, Dallas, Warren and Polk Counties. Lightning struck a house in Ankeny. The house was set on fire by the strike. | |||||||||||
| 37.7 | 1980-09-20 | 2 | 42°55'N / 94°07'W | 42°56'N / 94°00'W | 5.20 Miles | 80 Yards | 0 | 0 | 2.5M | 0 | Kossuth |
| 37.8 | 1999-07-02 | 2 | 42°34'N / 92°53'W | 42°33'N / 92°47'W | 4.50 Miles | 35 Yards | 0 | 0 | 25K | 1K | Butler |
| Brief Description: A very active weather pattern was in place over the central U.S. A strong west-northwest wind flow was in place over the state. Meanwhile a warm front was lifting north from the southern Plains. The warm front separated the cooler and dry air to the north from very humid air to the south. Dew point temperatures in the air to the south of the front were in the mid 70s to low 80s. Precipitable water values were near 2 inches as well. A meso scale convective system formed over north central Nebraska and south central South Dakota during the previous night. The remains of this system drifted into west central Iowa during the predawn hours. One cell became severe during the morning. This was to be the pattern for much of the rest of the day as the cells that formed became super cellular, with each supercell lasting about 2 hours. By the early afternoon hours, surface based CAPE values were approaching 6000 J/kg just to the south of the thunderstorm genesis region. Once the storms formed they became supercells quickly. Very strong sheer was in place with strong southeast surface winds veering to westerly winds in the mid levels. Even though freezing levels were in excess of 15,000 feet, the storms were prolific hail producers. WSR-88D VIL values with many of the supercells exceeded 90 kg/m/m. There was also some high winds with the storms at times as many of the cells were rotating as was seen with WSR-88D imagery. The first high winds occurred early in the severe event as 64 MPH winds blasted into the Dow City area of Crawford County. Winds of 66 MPH were recorded at the Denison Municipal Airport as the storm moved through. Damage was reported in many areas of the county. During the day there were also other spotty reports of wind damage, however most of the were were in the 40 to 50 MPH range. A few other cells did produce severe criteria winds as they moved into the central and northeast counties of the state with wind damage reported in Hardin, Hamilton, and Boone Counties. These storms developed during the period of time the weather system was changing from a supercell type system into more of a multi-cell system. The main severe weather event of the day was the hail. Hail reports of one inch up to golf ball size were too numerous to mention. Some of the hail was larger than tennis balls. Baseball size hail fell in Guthrie County, into Adair and Dallas Counties as one of the cells advanced east-southeast. The largest hail actually fell east of Casey in Guthrie County. Softball size hail fell there, smashing windshields on numerous cars. Needless to say, crop damage was widespread from west central into central Iowa along the paths of the two to three supercells that moved through the area. Scattered crop damage occurred with the multi-cellular storms over central into northeast Iowa as well. An example of the damage caused by the hail came by way of a report from Crawford County. Reports indicated hail damaged 80,000 to 100,000 acres of crops with widespread damage. Roads and ditches sustained between $150,000 and $200,000 in damage. Tree removal in the county was #30,000, with $100,000 damage to homes and businesses in the county. By the early evening, the weather system had made a transition from severe weather to heavy rain. Intense rainfall occurred over northeast Iowa. Flash flooding was widespread over northern Grundy, southern Butler, southern Bremer, and most of Black Hawk Counties. A large swath of 6 to 8 inch rainfall occurred over the Beaver Creek basin, causing flash flooding in the area and an eventual flood of near record proportions. County officials reported the flooding as very serious with countless roads and highways under water. Cars were stranded and thousands of basements were flooded by the onslaught of heavy rain. One report indicated several head of cattle lost as they were drown by the flood waters in Grundy County. No doubt, this was not the only case of livestock loss due to the flooding. Another report from the Dewar area, east of Waterloo, indicated about a block of railroad was washed out. Damage there was reported to 33 houses, a car repair shop, and a tavern. Rainfall was in excess of three inches per hour in many areas. The heaviest rainfall officially was around 9 inches. Some unofficial reports in the Cedar Falls area included up to 9 inches of rainfall in a 90 minute period. The observer at Parkersburg picked up 6.55 inches of rain in under 3 hours. A bucket survey in the area showed rainfall of 11 to 14 inches at a few locations in Butler County. The heavy rain occurred as a series of storms formed and trained over the same areas. The complex of thunderstorms that developed was a back developing complex. Late in the life of the system, one of the storms became severe. This storm displayed a meso circulation on the WSR-88D in Johnston, IA, though it was not all that well formed. The storm was the last in the series of storms and layed down a path of damage. The swath was about 13 miles long, extending across southern Butler and northern Grundy Counties. The damage path looked to be more downburst in nature, though there were reports of a tornado imbedded in the flow pattern. The situation was not all that different from the meso cyclone/tornado system that moved through Boone, Dallas, and Polk Counties about a year earlier on 29 June 1998. The tornado caused damage to several farmsteads along the road. The worst hit was on farmstead where all of the farm buildings were destroyed and only the superstructure of the farmhouse remained. Debris was wrapped up in trees for many miles along the path. One other tornado did occur earlier in the day. The tornado came from one of the supercells over western Iowa. A relatively small tornado touched down in Audubon County west of Hamlin. There was little damage reported with this tornado. | |||||||||||
| 37.8 | 1998-06-27 | 2 | 42°35'N / 92°56'W | 42°41'N / 92°32'W | 20.50 Miles | 75 Yards | 0 | 0 | 10K | 2K | Butler |
| Brief Description: Iowa was located in the warm sector of a developing storm system to the west. The warm front had moved to the northern Iowa border during the afternoon of the 27th with dew point temperatures in the mid 70s to around 80 blanketing the state in the warm sector. Initially, the airmass was capped, preventing thunderstorms from forming during the afternoon. Slightly cooler air moved in during the evening hours. In addition to the slightly cooler air moving in aloft, a cold front was poised over eastern Nebraska ready to move east into the state. Thunderstorms erupted rapidly by early evening with hail and high winds reported over northern Iowa. There were numerous reports of hail of an inch or larger in diameter, with a few reports of golf ball size hail. High winds were also a problem with many of the storms producing 60 to 70 MPH wind gusts. Reports of tree and power line damage were widespread. There were a few tornadoes as well. One tracked across open country in Cerro Gordo County before damaging a house south of Clear Lake. Another tornado touched down near Swaledale in Cerro Gordo County and passed southeast of Mason City. Much of the track was over open country, however one house was destroyed near Swaledale by this tornado. The longest track tornado moved across Butler and Bremer Counties. It also passed through open country, causing damage to crops and out buildings. In addition to these, there were a few brief touchdowns reported. Iowa soil remained very saturated with numerous rivers at or near flood stage. Heavy rainfall of near 4 inches in a couple hours time caused flash flooding in Cerro Gordo County. A widespread area of north central into northeast Iowa received heavy rainfall. Many areas picked up two to four inches of rain in a few hour period. This resulted in urban and small stream flooding, and ultimately general river flooding in the days that followed. As the storms moved through Worth County, lightning struck an outbuilding west of Kensett. The building was set on fire and destroyed. | |||||||||||
| 38.2 | 1984-06-07 | 2 | 42°52'N / 94°04'W | 42°53'N / 94°03'W | 1.00 Mile | 150 Yards | 0 | 0 | 2.5M | 0 | Kossuth |
| 38.7 | 1953-05-20 | 3 | 42°18'N / 93°18'W | 42°33'N / 93°03'W | 21.30 Miles | 400 Yards | 0 | 0 | 0K | 0 | Hardin |
| 39.2 | 1984-06-07 | 2 | 43°19'N / 93°58'W | 43°27'N / 93°45'W | 13.00 Miles | 150 Yards | 0 | 0 | 2.5M | 0 | Winnebago |
| 39.7 | 1967-04-30 | 4 | 43°30'N / 93°07'W | 43°34'N / 93°07'W | 4.60 Miles | 33 Yards | 0 | 0 | 25.0M | 0 | Freeborn |
| 40.2 | 1984-06-07 | 2 | 42°50'N / 94°07'W | 42°52'N / 94°04'W | 7.00 Miles | 150 Yards | 0 | 0 | 2.5M | 0 | Humboldt |
| 40.6 | 1984-06-07 | 2 | 43°13'N / 94°04'W | 43°19'N / 93°58'W | 8.00 Miles | 150 Yards | 0 | 1 | 2.5M | 0 | Kossuth |
| 41.4 | 1961-09-01 | 4 | 42°52'N / 92°33'W | 42°53'N / 92°28'W | 3.30 Miles | 27 Yards | 0 | 0 | 2.5M | 0 | Bremer |
| 41.5 | 1970-09-09 | 2 | 42°51'N / 92°32'W | 42°53'N / 92°29'W | 2.30 Miles | 150 Yards | 0 | 0 | 25K | 0 | Bremer |
| 41.7 | 1999-07-02 | 2 | 42°34'N / 92°49'W | 42°32'N / 92°39'W | 8.50 Miles | 50 Yards | 0 | 0 | 75K | 3K | Grundy |
| Brief Description: A very active weather pattern was in place over the central U.S. A strong west-northwest wind flow was in place over the state. Meanwhile a warm front was lifting north from the southern Plains. The warm front separated the cooler and dry air to the north from very humid air to the south. Dew point temperatures in the air to the south of the front were in the mid 70s to low 80s. Precipitable water values were near 2 inches as well. A meso scale convective system formed over north central Nebraska and south central South Dakota during the previous night. The remains of this system drifted into west central Iowa during the predawn hours. One cell became severe during the morning. This was to be the pattern for much of the rest of the day as the cells that formed became super cellular, with each supercell lasting about 2 hours. By the early afternoon hours, surface based CAPE values were approaching 6000 J/kg just to the south of the thunderstorm genesis region. Once the storms formed they became supercells quickly. Very strong sheer was in place with strong southeast surface winds veering to westerly winds in the mid levels. Even though freezing levels were in excess of 15,000 feet, the storms were prolific hail producers. WSR-88D VIL values with many of the supercells exceeded 90 kg/m/m. There was also some high winds with the storms at times as many of the cells were rotating as was seen with WSR-88D imagery. The first high winds occurred early in the severe event as 64 MPH winds blasted into the Dow City area of Crawford County. Winds of 66 MPH were recorded at the Denison Municipal Airport as the storm moved through. Damage was reported in many areas of the county. During the day there were also other spotty reports of wind damage, however most of the were were in the 40 to 50 MPH range. A few other cells did produce severe criteria winds as they moved into the central and northeast counties of the state with wind damage reported in Hardin, Hamilton, and Boone Counties. These storms developed during the period of time the weather system was changing from a supercell type system into more of a multi-cell system. The main severe weather event of the day was the hail. Hail reports of one inch up to golf ball size were too numerous to mention. Some of the hail was larger than tennis balls. Baseball size hail fell in Guthrie County, into Adair and Dallas Counties as one of the cells advanced east-southeast. The largest hail actually fell east of Casey in Guthrie County. Softball size hail fell there, smashing windshields on numerous cars. Needless to say, crop damage was widespread from west central into central Iowa along the paths of the two to three supercells that moved through the area. Scattered crop damage occurred with the multi-cellular storms over central into northeast Iowa as well. An example of the damage caused by the hail came by way of a report from Crawford County. Reports indicated hail damaged 80,000 to 100,000 acres of crops with widespread damage. Roads and ditches sustained between $150,000 and $200,000 in damage. Tree removal in the county was #30,000, with $100,000 damage to homes and businesses in the county. By the early evening, the weather system had made a transition from severe weather to heavy rain. Intense rainfall occurred over northeast Iowa. Flash flooding was widespread over northern Grundy, southern Butler, southern Bremer, and most of Black Hawk Counties. A large swath of 6 to 8 inch rainfall occurred over the Beaver Creek basin, causing flash flooding in the area and an eventual flood of near record proportions. County officials reported the flooding as very serious with countless roads and highways under water. Cars were stranded and thousands of basements were flooded by the onslaught of heavy rain. One report indicated several head of cattle lost as they were drown by the flood waters in Grundy County. No doubt, this was not the only case of livestock loss due to the flooding. Another report from the Dewar area, east of Waterloo, indicated about a block of railroad was washed out. Damage there was reported to 33 houses, a car repair shop, and a tavern. Rainfall was in excess of three inches per hour in many areas. The heaviest rainfall officially was around 9 inches. Some unofficial reports in the Cedar Falls area included up to 9 inches of rainfall in a 90 minute period. The observer at Parkersburg picked up 6.55 inches of rain in under 3 hours. A bucket survey in the area showed rainfall of 11 to 14 inches at a few locations in Butler County. The heavy rain occurred as a series of storms formed and trained over the same areas. The complex of thunderstorms that developed was a back developing complex. Late in the life of the system, one of the storms became severe. This storm displayed a meso circulation on the WSR-88D in Johnston, IA, though it was not all that well formed. The storm was the last in the series of storms and layed down a path of damage. The swath was about 13 miles long, extending across southern Butler and northern Grundy Counties. The damage path looked to be more downburst in nature, though there were reports of a tornado imbedded in the flow pattern. The situation was not all that different from the meso cyclone/tornado system that moved through Boone, Dallas, and Polk Counties about a year earlier on 29 June 1998. The tornado caused damage to several farmsteads along the road. The worst hit was on farmstead where all of the farm buildings were destroyed and only the superstructure of the farmhouse remained. Debris was wrapped up in trees for many miles along the path. One other tornado did occur earlier in the day. The tornado came from one of the supercells over western Iowa. A relatively small tornado touched down in Audubon County west of Hamlin. There was little damage reported with this tornado. | |||||||||||
| 41.7 | 1967-04-30 | 2 | 42°36'N / 94°02'W | 42°42'N / 93°59'W | 6.80 Miles | 200 Yards | 0 | 0 | 0K | 0 | Webster |
| 41.9 | 2010-06-17 | 2 | 43°30'N / 93°43'W | 43°31'N / 93°43'W | 1.00 Mile | 50 Yards | 0 | 0 | 0K | 0K | Faribault |
| Brief Description: EVENT NARRATIVE: A damage survey, plus photo and video evidence from storm chasers, showed that this tornado formed south-southwest of Kiester, near the intersection of 20th Street and 570th Avenue, then wrapped around another tornado (which developed about one mile west of Kiester) and dissipated. While southwest of Kiester, it did EF-2 damage to a couple farmsteads, including tree damage and destruction of several grain bins. EPISODE NARRATIVE: Several strong storms developed in west-central Minnesota during the mid afternoon hours of June 17th. These storms quickly become severe and produced softball size hail northwest of Alexandria and a tornado near Leaf Valley that became the EF-4 that moved through Wadena, Minnesota. By the late afternoon, numerous thunderstorms developed across southern Minnesota along the leading edge of extreme instability. Numerous funnel cloud reports and a few brief tornado touchdowns were noted prior to 5 pm, but once the low level shear (0-1 km) increased significantly from 15 knots, to over 35 knots, strong tornadoes developed along the Iowa border. These storms along the Iowa border produced a series of long-lived tornadoes near Albert Lea, Minnesota. Very large hail also accompanied some tornadoes along with flash flooding. | |||||||||||
| 42.0 | 1979-06-28 | 2 | 42°31'N / 93°48'W | 42°25'N / 93°44'W | 7.20 Miles | 350 Yards | 0 | 10 | 250K | 0 | Hamilton |
| 42.2 | 1964-08-29 | 4 | 42°55'N / 94°14'W | 43°07'N / 94°04'W | 15.80 Miles | 100 Yards | 0 | 2 | 250K | 0 | Kossuth |
| 42.5 | 2008-05-25 | 5 | 42°33'N / 92°51'W | 42°34'N / 92°33'W | 16.00 Miles | 1235 Yards | 9 | 50 | 75.0M | 75K | Butler |
| Brief Description: EVENT NARRATIVE: First EF5 tornado in Iowa since 13 June 1976. Nine deaths and 50 injuries occurred in Butler County. Tornado moved out of Butler County and continued in Black Hawk County. EPISODE NARRATIVE: A very intense upper low was located over the southwest U.S. and lifted northeast during the weekend of the 24th into the morning of the 26th. The seasons first strong push of deep moisture moved into Iowa on the 25th with surface temperatures warming into the mid 80s and dew points surging into the upper 60s to low 70s. Precipitable water values were near 1.5 inches. The dry slot pushed north across the area the previous night as the warm front lifted north. The primary surface low was located over northern Minnesota. A cold front extended south from the low into northwest Iowa. The airmass became very unstable by the mid afternoon hours. MUCAPE rose to between 4000 and 5000 J/kg. Lifted indices fell to -8 to -11 C. There was a considerable amount of both DCAPE at 1000-1500 J/kg and cape in the -10 to-30 C. layer of the atmoshpere, between 400 and 600 J/kg. The freezing level was around 13,200 feet. The environment was quite sheared with effective shear in the 40 to 50 kt range. LCL values were between 1000 and 1500 meters. The airmass was initially capped. During the late afternoon hours, a small cluster of thunderstorms formed over north central into northeast Iowa. The storms became severe very quickly. Initially, the storms dropped hail up to golf ball in size. One became a strong super cell and produced a major tornado. This cell, in addition to being tornadic, also produced hail of baseball to softball in size and winds in excess of 90 MPH. The tornado track was from approximately 2 miles south of Aplington to Parkersburg, then continued to New Hartford and across northern Black Hawk County. The average path width ranged from 0.6 to 0.7 miles near Parkersburg to just north of New Hartford. The path constricted to near one quarter mile wide east of New Hartford to north of Waterloo. The width then increased to near 1.2 miles wide north of Dunkerton before dissipating near the Black Hawk and Buchanan County line. The tornado was on the ground for approximately 43 miles. In addition to the main tornado, a satellite tornado was observed by storm chasers and one off duty NWS employee. It was located south of the main tornado and was on the ground for a little over a mile in Grundy County. Initial reports indicated 9 fatalities with 7 in Parkersburg (pop 1889) and 2 in New Hartford (pop 637). There were at least 50 injuries, with 4 of those in critical condition. Two of the fatalities occurred a few days after the tornado from injuries sustained in the tornado. The last fatality occurred on 7 Nov. A 61 year old female sustained injuries in the stairwell of her home when a 2 x 4 was thrown through her right side lung. She was hospitalized and died several months later of complications. Significant structural damage occurred across the southern end of Parkersburg and along a path to just north of New Hartford. Numerous structures completely destroyed from Parkersburg to near New Hartford. The tornado continued eastward to just north of the Waterloo and Cedar Falls area. Significant damage also occurred north of Dunkerton where the tornado increased to its greatest path width. This storm also produced substantial straight line wind damage along the southern periphery of the storm just south of the tornado track. News accounts indicated that a receipt from Parkersburg was found around 1915 CST 3 miles north of Prairie du Chien, WI, 109 miles to the northeast. Receipits were also found in Clayton County at Elkader, and full scrapbook pages and photos were found in far northeast Bremer County at Sumner. Preliminary estimates that straight line winds of 90 to 100 MPH occurred with this storm. At 1637 CST, the Waterloo Airport recorded a 93 MPH wind gust. Survey results suggest that straight line wind damage was the cause of the severe damage at the recreational vehicle dealership north of Cedar Falls. At least 627 homes were damaged, including 288 homes destroyed in Parkersburg, 88 in New Hartford, 15 in Hazelton and another 50 in Black Hawk County. In addition, 58 had major damage, 33 had moderate damage, 2 were inaccessible, and 93 damaged but able to be occupied. There were also 21 businesses destroyed. Governor Chet Culver declared both Butler and Black Hawk disaster areas with both given the State Declaration. A Federal Disaster Declaration occurred two days later for both Butler and Black Hawk Counties. The tornado was rated a low end EF5 by a Quick Response Team (QRT) in portions of Parkersburg and north of New Hartford with peak winds estimated at 205 MPH. For historical reference, the last F5 tornado to hit Iowa was on 13 June 1976 in Boone and Story Counties in the town of Jordan, with a 21 mile path length. The last F4 tornado to hit Iowa was in Union, Madison, and Dallas Counties with a 56 mile path length on 8 April 1999. There was one other smaller tornado during the evening. A tornado touched down in Clarke County and was on the ground for a short time southeast of Osceola. After the initial thunderstorm area developed over north central and northeast Iowa, a large complex developed over southeast Nebraska. The two areas of storms filled in to form a squall line by the mid evening hours. The complex over Nebraska then pushed east and northeast along the squall line. A considerable amount of severe weather was generated during the evening as this occurred. Along the squall line, high winds and hail were common with the dominant mode of severe weather being hail of up to golf ball in size. As the MCS out of Nebraska advanced east, a tail extending south from the centroid took on a bow echo configuration and raced east across Iowa at 65 MPH. Very high winds occurred with this feature with numerous locations reporting winds of 65 to 85 MPH. Some of the higher winds included an 85 MPH wind gust in the Winterset area and numerous reports of 75 to 85 MPH winds from Madison, Dallas, Warren and Polk Counties. Lightning struck a house in Ankeny. The house was set on fire by the strike. | |||||||||||
| 42.7 | 2001-05-01 | 2 | 43°34'N / 93°17'W | 43°37'N / 93°10'W | 7.00 Miles | 440 Yards | 0 | 0 | 20.0M | 0 | Freeborn |
| Brief Description: Tornado first touched down on the western fringe of Glenville, and produced major damage, especially on the northwest side of Glenville. There were 25 homes that sustained major damage, and 70 with minor damage. Damage survey indicated F2 damage on northwest side of Glenville, with F1 damage along rest of path. | |||||||||||
| 42.9 | 1968-05-15 | 5 | 43°10'N / 92°33'W | 43°13'N / 92°29'W | 4.10 Miles | 600 Yards | 0 | 0 | 0K | 0 | Chickasaw |
| 43.2 | 2010-06-17 | 2 | 43°31'N / 93°43'W | 43°33'N / 93°42'W | 3.00 Miles | 50 Yards | 0 | 0 | 0K | 0K | Faribault |
| Brief Description: EVENT NARRATIVE: A damage survey, plus photo and video evidence from chasers, showed this tornado developed just west of Kiester, moved north and struck the northwestern edge of Kiester, producing widespread tree damage and rated EF-1 at this point. It continued north as a multiple vortex tornado, doing EF-2 damage to a grove of trees. Farther north, several trees and grave stones were knocked over in a cemetery. It then turned and moved north-northeast before dissipating to the northeast of Kiester. It should be noted that another tornado which developed south-southwest of Kiester (see entry for 1710 to 1716 CST) wrapped around this tornado and dissipated west of Kiester. EPISODE NARRATIVE: Several strong storms developed in west-central Minnesota during the mid afternoon hours of June 17th. These storms quickly become severe and produced softball size hail northwest of Alexandria and a tornado near Leaf Valley that became the EF-4 that moved through Wadena, Minnesota. By the late afternoon, numerous thunderstorms developed across southern Minnesota along the leading edge of extreme instability. Numerous funnel cloud reports and a few brief tornado touchdowns were noted prior to 5 pm, but once the low level shear (0-1 km) increased significantly from 15 knots, to over 35 knots, strong tornadoes developed along the Iowa border. These storms along the Iowa border produced a series of long-lived tornadoes near Albert Lea, Minnesota. Very large hail also accompanied some tornadoes along with flash flooding. | |||||||||||
| 43.4 | 1966-10-14 | 2 | 42°23'N / 92°56'W | 42°26'N / 92°58'W | 2.70 Miles | 100 Yards | 0 | 0 | 3K | 0 | Grundy |
| 44.1 | 1979-06-28 | 2 | 42°25'N / 93°44'W | 1.00 Mile | 177 Yards | 0 | 0 | 250K | 0 | Hamilton | |
| 44.4 | 1965-05-05 | 4 | 43°23'N / 92°43'W | 43°23'N / 92°33'W | 7.90 Miles | 150 Yards | 0 | 0 | 25K | 0 | Floyd |
| 44.7 | 2001-09-06 | 2 | 42°42'N / 92°34'W | 42°47'N / 92°25'W | 10.00 Miles | 100 Yards | 0 | 0 | 100K | 10K | Bremer |
| Brief Description: Tornado moved in from Butler County and touched down again, mostly in open field. A car and garage was damaged in Bremer County. A strong upper level low pressure lifted northeast out of the southern Plains during the afternoon of the 6th. During the heating of the afternoon, thunderstorms erupted in the unstable air. The freezing level was around 15,000 feet, so hail was not a great threat. Surface dew point temperatures were in the upper 60s to low 70s with precipitable water values around 1.75 inches. Thunderstorms fired southwest of the Des Moines metropolitan area. A tornado touched down in rural Madison County. The tornado was about 60 feet wide and produced a half mile long path of damage in open country. As the storms moved northeast they continued to intensity. One cell dropped a tornado at the Glen Oaks Golf Course in West Des Moines, causing some minor damage there. The tornado tracked northeast and flipped a semi tractor-trailer truck in Interstate 35 resulting in one injury. It continued northeast and hit an apartment complex causing damage to the building and destroying an 8-car garage. The path was more intermittent as it continued northeast into the city. There were numerous reports of trees and power lines being downed. The tornado lifted as the event transitioned into a high wind event. The storms produced wind damage in Johnston as it moved through the area. High winds of 80 to 85 MPH occurred in northern Polk and southern Story Counties before they weakened. A grain bin was flattened, along with tree and crop damage, as the storm moved through the Elkhart area. Just northwest of that, in Slater, high winds took the roof off of a house in southern Story County. One person in the house was injured. The storms continued to track northeast, eventually dropping another tornado in Butler and Bremer Counties. The tornado had a somewhat intermittent track touching down south of Shell Rock and lifting northeast of Waverly. For the most part the tornado tracked through corn fields there. One farmstead was hit in Butler County. A grain bin was destroyed and blown one quarter of a mile across a field, another was blown off its foundation, a shed was destroyed, and crops were damaged. In Bremer County, one car and a garage were damaged along the tornadoes path. Another farmstead was hit north of Waverly. Part of a machine garage was destroyed and blown about 30 feet off of its foundation. | |||||||||||
| 44.9 | 1998-06-27 | 2 | 42°40'N / 92°34'W | 42°42'N / 92°29'W | 5.00 Miles | 75 Yards | 0 | 0 | 3K | 1K | Bremer |
| Brief Description: Iowa was located in the warm sector of a developing storm system to the west. The warm front had moved to the northern Iowa border during the afternoon of the 27th with dew point temperatures in the mid 70s to around 80 blanketing the state in the warm sector. Initially, the airmass was capped, preventing thunderstorms from forming during the afternoon. Slightly cooler air moved in during the evening hours. In addition to the slightly cooler air moving in aloft, a cold front was poised over eastern Nebraska ready to move east into the state. Thunderstorms erupted rapidly by early evening with hail and high winds reported over northern Iowa. There were numerous reports of hail of an inch or larger in diameter, with a few reports of golf ball size hail. High winds were also a problem with many of the storms producing 60 to 70 MPH wind gusts. Reports of tree and power line damage were widespread. There were a few tornadoes as well. One tracked across open country in Cerro Gordo County before damaging a house south of Clear Lake. Another tornado touched down near Swaledale in Cerro Gordo County and passed southeast of Mason City. Much of the track was over open country, however one house was destroyed near Swaledale by this tornado. The longest track tornado moved across Butler and Bremer Counties. It also passed through open country, causing damage to crops and out buildings. In addition to these, there were a few brief touchdowns reported. Iowa soil remained very saturated with numerous rivers at or near flood stage. Heavy rainfall of near 4 inches in a couple hours time caused flash flooding in Cerro Gordo County. A widespread area of north central into northeast Iowa received heavy rainfall. Many areas picked up two to four inches of rain in a few hour period. This resulted in urban and small stream flooding, and ultimately general river flooding in the days that followed. As the storms moved through Worth County, lightning struck an outbuilding west of Kensett. The building was set on fire and destroyed. | |||||||||||
| 45.0 | 1977-07-16 | 2 | 42°48'N / 92°29'W | 42°48'N / 92°26'W | 1.90 Miles | 20 Yards | 0 | 0 | 250K | 0 | Bremer |
| 45.1 | 1965-05-15 | 2 | 42°47'N / 94°10'W | 0.50 Mile | 100 Yards | 0 | 0 | 0K | 0 | Humboldt | |
| 45.7 | 1991-03-22 | 3 | 42°14'N / 93°22'W | 42°24'N / 93°09'W | 16.00 Miles | 70 Yards | 0 | 0 | 2.5M | 0 | Hardin |
| 46.2 | 1982-05-17 | 3 | 43°35'N / 93°17'W | 43°42'N / 93°08'W | 10.00 Miles | 100 Yards | 0 | 0 | 250K | 0 | Freeborn |
| 46.3 | 1984-06-07 | 3 | 43°12'N / 94°13'W | 43°19'N / 94°05'W | 9.00 Miles | 150 Yards | 0 | 5 | 25.0M | 0 | Kossuth |
| 46.6 | 1981-06-12 | 2 | 42°50'N / 94°13'W | 0 | 1 | 25K | 0 | Humboldt | |||
| 46.6 | 1998-05-15 | 2 | 43°01'N / 94°14'W | 43°28'N / 94°06'W | 31.30 Miles | 175 Yards | 0 | 0 | 1.0M | 75K | Kossuth |
| Brief Description: Intermittent track As the system mentioned above continued to evolve, a widespread outbreak of severe weather took place over Iowa. Strong upper level dynamics moved over the state over the top of an unstable air mass. Surface dew point temperatures were in the low 70s with actual temperatures in the upper 70s to low 80s. CAPE values rose to between 2500 and 3500 J/kg. The situation became complex during the afternoon as several bands of severe thunderstorms developed. Some areas of the state were affected three times during the day as the storms raced northeast around 60 MPH. The main severe feature with the storms was high wind. There were numerous reports of wind gusts of 60 to 75 MPH. Some were even higher. One of the highest reports came from Atlantic in Cass County. Ninety one MPH winds there threw several cars and a few semi-tractortrailer trucks off of Interstate 80. High winds in Kossuth County at Algona resulted in roof damage at a nursing home there. Part of the roof was removed by the winds with the damage estimates to the building places at around $200,000. Another cluster of storms moved into north central Iowa and caused widespread damage in Cerro Gordo and Worth Counties. Both were hit with winds around 70 MPH. There were numerous other reports of damage to farm buildings around the state ranging from corn cribs damaged to barns being destroyed. Damage to trees and power lines was extensive. North of Algona, along U.S. Highway 169, seventy eight power poles were downed by the high winds resulting in a four day closure of the highway. Utility damage around the county was estimated at between $600,000 and $800,000, while insurance adjusters estimated damage around the county at $1.2 million. There were some reports of hail, especially during the first few hours of the event. The largest hail was around golf ball in size. In addition to the wind and hail, there were several tornado touch downs in the state. A tornado touched down in Kossuth County and did over $1 million in damage. The tornado destroyed 2 houses with another 10 sustaining major damage. Fifteen farmsteads were destroyed as well. Kossuth County was later declared a disaster area. There was also considerable damage to barns and other farm buildings across the county. The outflow from the tornadic storm in Kossuth County pushed an 85 MPH wind gust south into Humboldt County. The high winds blew over 41 railroad cars of the Union Pacific Railroad south of Ottosen. A band of 80 to 90 MPH winds swept across Franklin and Butler Counties. Damage was widespread. There was one report of the wind carrying the family dog over one half mile from home. The dog was later found safe and healthy. Another of the stronger tornadoes included one in Wright County that was on the ground for over 10 miles. It damaged several farm buildings along its path. Several 2 x 4's were driven into the ground north of Clarion by the tornado. Another fairly strong tornado touched down in Crawford County. The rope tornado touched down southeast of Denison. It hit a train about 3 miles east of Denison and derailed nine cars of the Union Pacific freight train. The engineer saw it coming and thought it was so small that nothing would happen. There was also minor damage to 1 house and several out buildings. There were a few other brief touch downs around the state, however no damage was reported with them. The rapid movement of the storms prevented a lot of the flooding that would have otherwise occurred. Repeat thunderstorms passing over Kossuth County did cause some urban flooding. Damage was relatively minor, however several homes reported minor flooding. As the storms moved across Hancock County, lightning struck a house in the town of Britt. The kitchen sink was blown away from the wall and all of the appliances and the electrical equipment in the house was damaged. Lightning struck very close to another house in Wright County in Belmond. A 75-year old woman received minor injuries as she was struck by lightning as she unplugged her TV near a large window. | |||||||||||
| 46.9 | 1970-07-14 | 2 | 42°19'N / 93°26'W | 42°17'N / 93°23'W | 1.30 Miles | 250 Yards | 0 | 0 | 25K | 0 | Hardin |
| 47.0 | 1991-03-22 | 2 | 42°16'N / 92°59'W | 42°29'N / 92°47'W | 19.00 Miles | 50 Yards | 0 | 0 | 250K | 0 | Grundy |
| 48.1 | 1966-10-14 | 2 | 43°39'N / 93°36'W | 43°39'N / 93°31'W | 2.70 Miles | 33 Yards | 0 | 1 | 3K | 0 | Freeborn |
| 48.4 | 2001-05-01 | 2 | 43°39'N / 93°08'W | 43°40'N / 93°03'W | 5.00 Miles | 250 Yards | 0 | 0 | 2.0M | 0 | Freeborn |
| Brief Description: Shortly after the Glenville tornado dissipated, another tornado formed 4 miles southwest of Oakland and dissipated about 1/2 mile before it would have crossed Interstate 90, which law enforcement had barricaded. Major damage to 3 farmsteads, minor damage to 8 others per damage survey. | |||||||||||
| 48.5 | 1971-07-12 | 4 | 43°14'N / 92°27'W | 43°13'N / 92°23'W | 2.30 Miles | 1320 Yards | 0 | 4 | 2.5M | 0 | Howard |
| 48.7 | 1974-06-22 | 2 | 42°18'N / 93°39'W | 42°19'N / 93°36'W | 0 | 0 | 250K | 0 | Hamilton | ||
| 49.6 | 1984-06-07 | 2 | 43°38'N / 92°59'W | 43°39'N / 92°54'W | 5.00 Miles | 100 Yards | 0 | 7 | 2.5M | 0 | Mower |
* The information on this page is based on the global volcano database, the U.S. earthquake database of 1638-1985, and the U.S. Tornado and Weather Extremes database of 1950-2010.