EF1 tornado, Hancock, Minnesota, June 13, 2017

1. EF065 to 85 mph

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

2. EF186 to 110 mphthis tornado

   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

EF1

Date

June 13, 2017

Touchdown

6:56 PM CDT (23:56 UTC)

Lifted

7:04 PM CDT (00:04 UTC)

On the ground

8 minutes

Path length

3.0 miles (4.8 km)

Path width

300 yards (274 m)

Deaths

0

Injuries

0

County

Stevens County

Touchdown point

45.567, -95.797

Lift-off point

45.608, -95.778

Record number

1706131756-01

7 damage points were recorded along this path by NWS MPX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 90 mph.

• Beginning point. Tree debris seen on video.
• End point. Brief tornado per video evidence, no damage.
• Beginning point. Brief spin up based on video evidence, no damage.
• Tornado over Long Lake just west of county road 1. No debris in the air.

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

A sunrise thunderstorm near Morris, Minnesota produced nickel size hail as a few storms moved across the area. ||During the afternoon of Tuesday, June 13th, a Supercell type storm developed near Montevideo in west central Minnesota, and moved north. It produced two tornadoes near Morris. Several other reports of downed trees were noted in Douglas County as the tornado dissipated but straight line winds developed from the outflow. Later that evening, a line of thunderstorms moved from eastern South Dakota, into west central Minnesota, and eventually across southern Minnesota, and into west central Wisconsin. Although most of the reports were sub-severe with some damage near Bellingham, or in far western Lac Qui Parle County, this line redeveloped west of the Twin Cities. As the storm intensified, it produced several severe wind gusts that caused trees and power lines to blow down around the Twin Cities metro area. A few more significant damage reports came from central Scott, and central Dakota counties where a shed was blown down, and some structural damage near Farmington, and Vermillion.

Multiple videos showed a tornado moving across some fields.

Multiple videos from storm chasers and others showed this tornado mostly moved along the eastern shore of Long Lake, east of Morris. Occasional tree damage occurred on the eastern shore, where over 100 trees, including some oaks, were broken or uprooted. More trees were felled on the northeast end of Long Lake. An electrical substation just northeast of Long Lake was damaged shortly before the tornado dissipated. Two barn doors were blown off and some shingles were removed from a house.

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

38 minutes of warning. NWS MPX issued a tornado warning for this county at 23:18 UTC, 38 minutes before the tornado touched down, in force until 00:15 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 Enhanced Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:57 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 Minneapolis radar (KMPX), 192 km away, was scanning. The volume nearest the touchdown began at 23:53 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 2017 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

12 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.