EF0 tornado, Florian to Newfolden, Minnesota, June 21, 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

June 21, 2010

Touchdown

3:59 PM CDT (20:59 UTC)

Lifted

4:05 PM CDT (21:05 UTC)

On the ground

6 minutes

Path length

2.1 miles (3.5 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

County

Marshall County

Touchdown point

48.430, -96.690

Lift-off point

48.440, -96.645

Record number

1006211459-01

Afternoon (June 21st) water vapor imagery showed a nice circulation rotating through the northern Red River Valley into northwest Minnesota. At the surface, there was also a weak low pressure system over the central Red River Valley by mid afternoon with an inverted trough extending its north. After some morning clouds, enough clearing occurred by afternoon to allow temperatures to rise into the mid to upper 70s with dew points in the mid 60s. As thunderstorm cells formed, many took on a classic hook shape, denoting possible circulations. Most of the stronger rotating cells occurred right along the weak surface boundary, but others did along more subtle boundaries.

The tornado broke down several poplar trees in shelterbelts west of and adjacent to the Marshall County park and campground on the Tamarac River. Peak winds were estimated at 85 mph.

Several brief touchdowns occurred along this roughly two mile path. Peak winds were estimated at 75 mph.

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

42 minutes of warning. NWS FGF issued a tornado warning for this county at 20:17 UTC, 42 minutes before the tornado touched down, in force until 21:00 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 22:48 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.

Hallock (HCO), 41 km from the path, in the two hours either side.

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

The Fargo/Grand Forks radar (KMVX), 112 km away, was scanning. The volume nearest the touchdown began at 20:58 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

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 MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

26 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.