Tornadoes · United States · Wisconsin · 2026
EF0 tornado, Marathon County, Wisconsin, July 20, 2026
This EF0 tornado ran 8.2 miles across Marathon County on July 20, 2026, touching down at 7:15 PM CDT and reaching 25 yards wide. It killed nobody.
Preliminary. This is NWS GRB's damage survey, filed in the Damage Assessment Toolkit as Stratford_Tornado. The rating, the path and the casualties are the survey's and can change while it is revised. The Storm Prediction Center compiles the official record of 2026 from these surveys and publishes it in the spring of 2027; this page moves to that tornado's permanent address when it does.
The rating scale
Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
EF065 to 85 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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.
The survey
- Rating, as surveyed
- EF0, preliminary
- Date
- July 20, 2026
- Touchdown
- 7:15 PM CDT (00:15 UTC)
- Lifted
- 7:44 PM CDT (00:44 UTC)
- On the ground
- 29 minutes
- Path length
- 8.2 miles (13.2 km)
- Path width
- 25 yards (23 m)
- Deaths
- 0
- Injuries
- 0
- County
- Marathon County
- Touchdown point
- 44.835, -90.191
- Lift-off point
- 44.809, -90.029
- Highest wind the damage implies
- 65 mph
- Surveyed by
- NWS GRB
- The office's name for it
- Stratford_Tornado
- Survey last edited
- August 29, 2026
- Record number
- None yet. SPC numbers 2026 in the spring of 2027.
What the survey found
At approximately 7:15 PM CDT a small tornado touched down at the Wisconsin Farm Technology Days. The tornado produced minor damage to one tent and a few portable restrooms. There were subsequently several reports of tornadoes in the Stratford area from this tall, skinny thunderstorm. Location and path determined from photos, video, and radar time-matching.
Written by NWS GRB in the NWS Damage Assessment Toolkit. A survey is revised as better evidence arrives.
The damage survey
1 damage points were recorded along this path by NWS GRB, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 65 mph.
- At approximately 7:15 PM CDT a small tornado touched down at the Wisconsin Farm Technology Days. The tornado produced minor damage to one tent and a few portable restrooms.
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
The forecast that day
The Storm Prediction Center had this point in a Enhanced Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. 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 air that afternoon
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.
Green Bay/Straub, WI (KGRB), 00:00Z
0.3 hours before the tornado, 163 km from the path. July 21, 2026.
- Mixed-layer CAPE
- 1492 J/kg
- Mixed-layer CIN
- -124 J/kg
- Surface CAPE
- 1854 J/kg
- Mixed-layer LCL
- 1140 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 338 m²/s²
- 0-3 km storm-relative helicity
- 464 m²/s²
- Significant tornado parameter
- 1.4
- Supercell composite
- 15.7
- 0-3 km lapse rate
- 6.2 K/km
The surface observations
Marshfield (MFI), 21 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 00:00 UTC |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The La Crosse radar (KARX), 140 km away, was scanning. The volume nearest the touchdown began at 00:15 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.
This ground now
The live radar over the trackEvery 2026 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are
The other tornadoes of July 20, 2026
13 more have been surveyed in the United States that day, so far.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| July 20 | 3:35 PM CDT | EF1 | Franklin, IA | 0.4 | 25 | |||
| July 20 | 3:49 PM CDT | EF1 | Butler, IA | 3.1 | 25 | |||
| July 20 | 3:56 PM CDT | EF1 | Butler, IA | 4.4 | 25 | |||
| July 20 | 4:00 PM CDT | Unrated | Grundy, IA | 2.0 | 0 | |||
| July 20 | 6:31 PM EDT | Unrated | Marquette, MI | 2.8 | 0 | |||
| July 20 | 6:47 PM CDT | EF1 | Menominee, MI | 0.1 | 35 | |||
| July 20 | 6:48 PM CDT | EF0 | Wabasha, MN | 2.3 | 20 | |||
| July 20 | 7:58 PM EDT | EF1 | Delta, MI | 0.3 | 0 | |||
| July 20 | 7:03 PM CDT | Unrated | Marathon, WI | 2.0 | 0 | |||
| July 20 | 7:11 PM CDT | EF0 | Trempealeau, WI | 0.9 | 20 | |||
| July 20 | 7:47 PM CDT | EF0 | Jackson, WI | 2.3 | 50 | |||
| July 20 | 7:57 PM CDT | EF0 | Menominee, WI | 7.8 | 20 | |||
| July 20 | 8:26 PM CDT | Unrated | Shawano, WI | 8.8 | 0 |
What this means
Ratings are the survey's, read off the damage rather than measured; the rating scale is above. A survey can be revised, so the rating, the path and the casualties can all still change.
Sources
NWS Damage Assessment Toolkit, the record the survey teams file from the damage, and NOAA Storm Prediction Center storm reports. Neither is the official database for 2026, which SPC publishes in the spring of 2027.