Grant County Natural Disasters and Weather Extremes
The chance of earthquake damage in Grant County is about the same as South Dakota average and is much lower than the national average. The risk of tornado damage in Grant County is lower than South Dakota average and is lower than the national average.
Earthquake Index, #40
| Grant County | 0.01 |
| South Dakota | 0.05 |
| 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
| Grant County | 0.0000 |
| South Dakota | 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, #30
| Grant County | 83.31 |
| South Dakota | 114.73 |
| 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 8,398 other weather extremes events within 50 miles of Grant County 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: | 90 | Cold: | 30 | Dense Fog: | 2 | Drought: | 14 |
| Dust Storm: | 0 | Flood: | 520 | Hail: | 4,176 | Heat: | 10 | Heavy Snow: | 80 |
| High Surf: | 0 | Hurricane: | 0 | Ice Storm: | 13 | Landslide: | 0 | Strong Wind: | 93 |
| Thunderstorm Winds: | 2,915 | Tropical Storm: | 0 | Wildfire: | 6 | Winter Storm: | 118 | Winter Weather: | 82 |
| Other: | 249 | ||||||||
Volcanos Nearby
No volcano is found in or near Grant County.
Historical Earthquake Events
A total of 1 historical earthquake event that had a recorded magnitude of 3.5 or above found in or near Grant County.
| Distance (miles) | Date | Magnitude | Depth (km) | Latitude | Longitude |
| 49.4 | 1975-07-09 | 5 | N/A | 45.67 | -96.04 |
Historical Tornado Events
A total of 21 historical tornado events that had recorded magnitude of 2 or above found in or near Grant County.
| Distance (miles) | Date | Magnitude | Start Lat/Log | End Lat/Log | Length | Width | Fatalities | Injuries | Property Damage | Crop Damage | Affected County |
| 10.0 | 1955-08-28 | 2 | 45°07'N / 96°35'W | 1.50 Miles | 33 Yards | 0 | 0 | 25K | 0 | Grant | |
| 13.3 | 1979-08-03 | 2 | 45°24'N / 96°52'W | 45°18'N / 96°28'W | 20.50 Miles | 33 Yards | 0 | 0 | 250K | 0 | Roberts |
| 13.7 | 1951-07-08 | 2 | 45°22'N / 96°50'W | 0 | 1 | 0K | 0 | Roberts | |||
| 23.3 | 1962-08-06 | 2 | 45°03'N / 97°13'W | 0 | 0 | 250K | 0 | Codington | |||
| 24.3 | 1956-10-29 | 2 | 45°31'N / 96°40'W | 0 | 0 | 0K | 0 | Big Stone | |||
| 24.7 | 1979-06-19 | 2 | 44°54'N / 97°06'W | 0 | 0 | 2.5M | 0 | Codington | |||
| 26.1 | 1996-05-17 | 3 | 45°23'N / 96°34'W | 45°33'N / 96°18'W | 17.00 Miles | 200 Yards | 0 | 0 | 1.5M | 0 | Big Stone |
| Brief Description: A tornado crossing Big Stone Lake from Roberts County, South Dakota destroyed one cabin at the Meadowbrook Resort, blew the roof off another cabin, and another cabin was demolished when a big tree fell onto it. Several boats on Big Stone Lake were overturned. Approxiamately 150 buildings sustained damage or were destroyed as the tornado moved northeast across Big Stone County through the townships of Prior, Big Stone, Almond, Malta, and Moonshine. Southwest of Clinton, a pontoon boat and a camper were destroyed. East of Clinton, a farm lost all buildings with severe damage to their home. The cupboards fell off the walls and doors would not close, signifying a twisted frame. Northeast of Clinton, another farm suffered damage to all structures. Half of the roof was torn off their home. Two miles south of Johnson, a house (rambler) was completely destroyed and several barns and machine sheds were destroyed, before the tornado lifted. Many trees were uprooted in the path of the tornado across Big Stone County and much of the power was out in the County as power lines were downed. | |||||||||||
| 26.9 | 1983-07-18 | 3 | 44°54'N / 97°10'W | 0.50 Mile | 100 Yards | 0 | 0 | 2.5M | 0 | Codington | |
| 31.3 | 1981-07-22 | 2 | 44°47'N / 97°06'W | 0 | 0 | 250K | 0 | Hamlin | |||
| 38.1 | 2004-09-23 | 2 | 45°42'N / 96°44'W | 45°45'N / 96°48'W | 2.20 Miles | 50 Yards | 0 | 0 | 0 | 0 | Roberts |
| Brief Description: The storm entered South Dakota from Traverse county, Minnesota where it produced a tornado. The storm produced a second tornado as it crossed Lake Traverse into South Dakota. This tornado was stronger and destroyed a house, a mobile home, and a travel trailer. Another house and travel trailer were damaged and a shed was also ripped apart. The tornado also killed three cattle. | |||||||||||
| 38.3 | 1984-05-12 | 3 | 44°50'N / 97°30'W | 44°48'N / 97°15'W | 13.00 Miles | 1320 Yards | 0 | 0 | 2.5M | 0 | Codington |
| 38.5 | 1951-07-20 | 2 | 44°54'N / 96°05'W | 1.00 Mile | 33 Yards | 0 | 4 | 0K | 0 | Codington | |
| 40.5 | 1964-06-08 | 2 | 44°58'N / 97°33'W | 0 | 0 | 0K | 0 | Clark | |||
| 42.1 | 1971-06-19 | 2 | 44°34'N / 96°52'W | 0 | 0 | 3K | 0 | Deuel | |||
| 42.2 | 1986-07-18 | 2 | 44°34'N / 96°42'W | 44°35'N / 96°29'W | 17.00 Miles | 150 Yards | 0 | 0 | 25K | 0 | Deuel |
| 44.0 | 1964-06-08 | 2 | 45°05'N / 97°40'W | 0.50 Mile | 33 Yards | 0 | 0 | 0K | 0 | Clark | |
| 45.7 | 1964-05-05 | 2 | 45°48'N / 96°52'W | 45°52'N / 96°49'W | 4.50 Miles | 100 Yards | 0 | 0 | 25K | 0 | Roberts |
| 45.9 | 1964-06-08 | 2 | 44°47'N / 97°32'W | 0 | 0 | 0K | 0 | Clark | |||
| 46.4 | 1971-06-19 | 2 | 44°38'N / 97°06'W | 44°22'N / 96°27'W | 36.80 Miles | 33 Yards | 0 | 0 | 0K | 0 | Hamlin |
| 46.6 | 1984-05-12 | 3 | 44°53'N / 97°44'W | 44°50'N / 97°30'W | 14.00 Miles | 1320 Yards | 0 | 0 | 2.5M | 0 | Clark |
| 48.0 | 1986-07-18 | 2 | 44°34'N / 97°27'W | 44°35'N / 97°06'W | 14.00 Miles | 100 Yards | 0 | 0 | 25K | 0 | Hamlin |
* 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.