EF0 tornado, Rolette, North Dakota, August 1, 2010

1. EF065 to 85 mphthis tornado

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

2. EF186 to 110 mph

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

3. EF2111 to 135 mph

   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. EF3136 to 165 mph

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

5. EF4166 to 200 mph

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

6. EF5over 200 mph

   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.

Rating

EF0

Date

August 1, 2010

Touchdown

9:45 PM CDT (02:45 UTC)

Lifted

10:01 PM CDT (03:01 UTC)

On the ground

16 minutes

Path length

5.8 miles (9.3 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

County

Rolette County

Touchdown point

48.710, -99.830

Lift-off point

48.698, -99.704

Record number

1008012045-01

In the mid afternoon hours of Sunday, August 1st, Severe Thunderstorm Watch number 559 was issued for much of western and north central North Dakota. Later, during early Sunday evening, the watch was expanded to include south central North Dakota. A remnant outflow boundary across northeast Montana and northwest North Dakota was the focus for isolated supercells as they tracked east-southeast from northwest North Dakota in the afternoon, into south central North Dakota in the evening. Additional thunderstorm development took place across north central North Dakota, where mid level short wave impulses provided the necessary lift along a surface trough.||Several severe thunderstorm and tornado warnings were issued. Multiple reports of large hail, several reports of severe thunderstorm winds, and two confirmed tornadoes occurred during this episode.

This tornado occurred in the open country. No structures were impacted, so no damage was done. The Rolla Fire Department was also reporting this tornado to the National Weather Service in real time.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

9 minutes of warning. NWS BIS issued a tornado warning for this county at 02:36 UTC, 9 minutes before the tornado touched down, in force until 03:00 UTC.

The county was under a severe thunderstorm watch, issued at 22:12 UTC and running to 03:47 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 00:52 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Devils_lake (DVL), 91 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2010 tornado in North DakotaEvery tornado in North Dakota since 1950Warnings in force in North Dakota nowThe forecast where you are

2 more were confirmed in the United States that day.

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.