EF0 tornado, Swift Falls, Minnesota, August 6, 2015

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 6, 2015

Touchdown

4:09 PM CDT (21:09 UTC)

Lifted

4:10 PM CDT (21:10 UTC)

On the ground

1 minutes

Path length

0.1 miles (0.2 km)

Path width

15 yards (14 m)

Deaths

0

Injuries

0

County

Swift County

Touchdown point

45.361, -95.281

Lift-off point

45.361, -95.278

Record number

1508061509-01

8 damage points were recorded along this path by NWS MPX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0.

• Tornado Start - No damage survey was conducted
• Tornado End - No damage survey was conducted

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

The afternoon of Thursday, August 6th, severe thunderstorms began to develop across northeast South Dakota and move east into west central Minnesota. Two thunderstorms, one near Elbow Lake, and another near Benson, moved eastward and caused damage near Evansville, and a brief tornado touchdown west of Sunburg. The Evansville storm weakened as it moved eastward into Todd County. The storm west of Sunburg, moved slowly eastward and produced several brief tornado touchdowns, mainly in open fields. However, the town of Hawick had some minor damage associated with the brief tornado that touchdown. Other storms produced damage near Canby as they moved from eastern South Dakota, into west central Minnesota.

The tornado briefly touched down in a corn field and was caught on video by multiple storm chasers. It was also witnessed by fire department personnel.

The tornado briefly touched down in a corn field and was caught on video by multiple storm chasers.

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

0 minutes of warning. NWS MPX issued a tornado warning for this county at 21:09 UTC, 0 minutes before the tornado touched down, in force until 21:32 UTC.

The county was under a severe thunderstorm watch, issued at 20:27 UTC and running to 03:00 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:00 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.

Benson Municipal (BBB), 29 km from the path, in the two hours either side.

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

The Minneapolis radar (KMPX), 146 km away, was scanning. The volume nearest the touchdown began at 21:10 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 2015 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

10 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.