EF0 tornado, Grellton to Sullivan, Wisconsin, July 29, 2021

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

July 29, 2021

Touchdown

1:05 AM CDT (06:05 UTC)

Lifted

1:13 AM CDT (06:13 UTC)

On the ground

8 minutes

Path length

6.0 miles (9.6 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

County

Jefferson County

Touchdown point

43.175, -88.802

Lift-off point

43.124, -88.707

Record number

2107290005-01

99 damage points were recorded along this path by NWS MKX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 110 mph.

• North side Basement blew in as well.
• Edge of corn crop pushed down in multiple directions.
• Metal sheeting wrapped around downed power pole.
• Two garages and one large horse barn collapsed. Debris throw into field to the SSE. Garage was bolted into foundation, but wood was rotten.

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

A round of severe storms tracked into southwest Wisconsin during the early morning hours on July 28th. Followed by another round of stronger, more widespread thunderstorms that begin to dive south across central Wisconsin late in the evening on July 28th through the early morning hours on July 29th.

This was 1 of 17 tornadoes to occur in Wisconsin on the night of July 28th into the early morning hours of July 29th. This was the 11th overall tornado for the event. A line of storms developed in northern Wisconsin and pushed south into southern Wisconsin in the overnight hours of the 28th into the 29th of July with mainly brief tornadoes and damaging winds occurring.| |This tornado began to the southwest of Watertown and mainly moved through rural areas to the south of the city. Some of the main damage was to a house/farm near Hilltop Rd and Horseshoe Rd, otherwise it was mainly tree and crop damage. The path cross Highway 26 near Ebenezer Rd and ended near Cattail Dr.

This was 1 of 17 tornadoes to occur in Wisconsin on the night of July 28th into the early morning hours of July 29th. This was the 12th overall tornado for the event. A line of storms developed in northern Wisconsin and pushed south into southern Wisconsin in the overnight hours of the 28th into the 29th of July with mainly brief tornadoes and damaging winds occurring. ||This tornado began near Highway 26 north of I-94 and eventually crossed I-94 near Saucer Dr. Mainly tree damage along this path.

This was 1 of 17 tornadoes to occur in Wisconsin on the night of July 28th into the early morning hours of July 29th. This was the 13th overall tornado for the event. A line of storms developed in northern Wisconsin and pushed south into southern Wisconsin in the overnight hours of the 28th into the 29th of July with mainly brief tornadoes and damaging winds occurring. ||This tornado began a few country blocks east of tornado #12 and started near County Highway P near Aliceton Dr and then tracked to the south, damaging a number of structures along County Rd E, crossing I-94 before going through Concord. The tornado then went through rural areas before ending east of Willow Glen Rd.

This was 1 of 17 tornadoes to occur in Wisconsin on the night of July 28th into the early morning hours of July 29th. This was the 14th overall tornado for the event. A line of storms developed in northern Wisconsin and pushed south into southern Wisconsin in the overnight hours of the 28th into the 29th of July with mainly brief tornadoes and damaging winds occurring. ||This tornado began near Indian Point Rd to the southwest of Golden Lake in the far eastern part of Jefferson county. It crossed the Jefferson/Waukesha County line to the NW of the Bark River. Damage noted in this area by Indian Point Rd was to trees.

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

22 minutes of warning. NWS MKX issued a tornado warning for this county at 05:43 UTC, 22 minutes before the tornado touched down, in force until 06:15 UTC.

The county was under a severe thunderstorm watch, issued at 00:22 UTC and running to 07:00 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 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.

Watertown (RYV), 3 km from the path, in the two hours either side.

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

The Milwaukee radar (KMKX), 26 km away, was scanning. The volume nearest the touchdown began at 06:07 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 2021 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

36 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.