EF1 tornado, Woodbury to River Falls, Minnesota, July 18, 2020

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

July 18, 2020

Touchdown

9:54 PM CDT (02:54 UTC)

Lifted

10:20 PM CDT (03:20 UTC)

On the ground

26 minutes

Path length

9.5 miles (15.2 km)

Path width

400 yards (366 m)

Deaths

0

Injuries

0

Property damage

$100,000

Counties

Washington and Pierce counties

Touchdown point

44.817, -92.846

Lift-off point

44.834, -92.656

Record number

2007182054-01

42 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 100 mph.

• Large tree limb snapped. Fell to the south. No evidence of damage to nearby trees or fields
• Convergent crop damage. Damage path extends out to trees on the horizon to the west. Path width roughly 50 yds wide. Power lines were also down at the location but have since been repaired (DOD estimated 70-85 mph)
• Upper portion of a few small pine trees snapped off. About 50 yds south of crop damage so path width probably closer to 100 yds
• Damage Path appears to begin at farmstead located roughly 200 yds to the south of the road. Tree damage & sheet metal consistent with high EF0 winds.

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

A cold front moved southeast across eastern Minnesota, and western Wisconsin during the late afternoon, and evening of Saturday, July 18th. Along this front, a line of severe thunderstorms develop which initially was producing large hail, but became tornadic during the evening in parts of the eastern Twin Cities metro area.

A cold front moved southeast across eastern Minnesota, and western Wisconsin during the late afternoon, and evening of Saturday, July 18th. Along this front, a line of severe thunderstorms develop which initially was producing large hail, but became tornadic during the evening north of Prescott, Wisconsin. This is the continuation of the Washington County tornado in east central Minnesota.

A tornado damaged about one dozen trees, soffit was ripped off a house, a semi was tipped over, and about six greenhouse hoops were damaged.

A NWS Storm Survey indicated that an EF1 tornado occurred in far southern Washington County, in a rural area, north of Hastings, Minnesota. ||The tornado spun up 5 miles north of Hastings, Minnesota, and tracked eastward for 3.2 miles until it moved across the St. Croix River, and into Wisconsin. Extensive tree damage occurred along its path, with the heaviest damage on top of the bluff as it moved across the St. Croix River into Wisconsin. A few farm outbuildings were also damaged. The tornado had a maximum speed of 100 mph, with a maximum width of 400 yards.

This is the continuation of the tornado that moved across southern Washington County, and into Wisconsin. The path of the tornado continued to move east-northeast before dissipating 1.7 miles southwest of River Falls, Wisconsin. Trees were uprooted along the continuous path which was 6.2 miles long.

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 02:53 UTC, 1 minute before the tornado touched down, in force until 03:07 UTC.

The county was under a severe thunderstorm watch, issued at 20:54 UTC and running to 03:32 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:04 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.

St Paul / Lake Elmo (21D), 21 km from the path, in the two hours either side.

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

The Minneapolis radar (KMPX), 64 km away, was scanning. The volume nearest the touchdown began at 02:51 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 2020 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

5 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.