EF0 tornado, Chokio, Minnesota, August 6, 2013

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, 2013

Touchdown

4:00 PM CDT (21:00 UTC)

Lifted

4:01 PM CDT (21:01 UTC)

On the ground

1 minutes

Path length

0.1 miles (0.1 km)

Path width

10 yards (9 m)

Deaths

0

Injuries

0

County

Stevens County

Touchdown point

45.613, -96.136

Lift-off point

45.613, -96.134

Record number

1308061500-01

3 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 end. No damage survey was conducted.
• Tornado start. 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.

Severe thunderstorms developed in far northeast South Dakota, and moved east-southeast across west-central, and into central and east-central Minnesota during the afternoon and evening hours of Tuesday, August 6th.||One of the storms was long-lived and produced a swath of very large hail from Morris, southeast to the Twin Cities Metro area aninto Wisconsin. Numerous vehicles and homes were damaged from golf ball, up to baseball size hail in the southern metropolitan area. In Bloomington, hail smashed windows in the Wells Fargo Plaza, leaving broken glass in the 24-story building's entry ways. The storms also brought high winds, which knocked over large trees in areas across the Metro area. Xcel Energy reported over 70,000 customers from St. Cloud through the Twin Cities area were without power during the height of the storm.

Two different photographers took pictures of a tornado northeast of Chokio. One dairy farmer reported that the door to the milk house was blown off along with other minor damage. It was on the ground for only about 30 seconds.

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

1 minute of warning. NWS MPX issued a tornado warning for this county at 20:59 UTC, 1 minute before the tornado touched down, in force until 21:30 UTC.

The county was under a tornado watch, issued at 19:25 UTC and running to 02:00 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 19:52 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.

The Aberdeen radar (KABR), 178 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 2013 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.