Tornadoes in Grand Forks County, North Dakota

1. F0 / EF040 to 72 mph on the F scale, 65 to 85 mph on the EF scale

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. F1 / EF173 to 112 mph on the F scale, 86 to 110 mph on the EF scale

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. F2 / EF2113 to 157 mph on the F scale, 111 to 135 mph on the EF scale

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. F3 / EF3158 to 206 mph on the F scale, 136 to 165 mph on the EF scale

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. F4 / EF4207 to 260 mph on the F scale, 166 to 200 mph on the EF scale

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. F5 / EF5261 to 318 mph on the F scale, over 200 mph on the EF scale

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Tornadoes

93

Deaths

1

Injuries

21

F4 and above

2

Worst on record

EF4, August 26, 2007

1. EF4 Northwood tornado, North DakotaAugust 26, 20071 killed, 18 injured

1. EF4 Mayville–Thompson tornado, North DakotaJune 17, 2010EF4, 17.0 mi (27 km)
2. EF4 Northwood tornado, North DakotaAugust 26, 2007EF4, 5.0 mi (8 km)
3. EF3, Nelson and Grand Forks counties, North DakotaAugust 26, 2007EF3, 6.0 mi (10 km)
4. F3, Grand Forks County, North DakotaAugust 11, 1958F3, 0.1 mi (0 km)
5. EF2, Grand Forks County, North DakotaJune 17, 2010EF2, 7.0 mi (11 km)
6. EF2, Grand Forks and Polk counties, North Dakota and MinnesotaAugust 26, 2007EF2, 5.0 mi (8 km)
7. F2, Grand Forks County, North DakotaJune 30, 1955F2, 4.1 mi (7 km)
8. EF2, Grand Forks County, North DakotaJune 27, 2015EF2, 3.0 mi (5 km)
9. EF2, Grand Forks County, North DakotaAugust 10, 2010EF2, 0.9 mi (1 km)
10. F2, Grand Forks County, North DakotaMay 26, 1978F2, 0.5 mi (1 km)

Warnings in force in Grand Forks CountyThe forecast for Grand Forks CountyThe live radar over Grand Forks CountyEvery county in North Dakota

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.