EF2 tornado, Loyal to Colby, Wisconsin, May 15, 2025

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 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mphthis tornado

   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

EF2

Date

May 15, 2025

Touchdown

5:21 PM CDT (22:21 UTC)

Lifted

5:28 PM CDT (22:28 UTC)

On the ground

7 minutes

Path length

4.6 miles (7.4 km)

Path width

230 yards (210 m)

Deaths

0

Injuries

0

Property damage

$725,000

Crop damage

$100,000

Counties

Clark and Marathon counties

Touchdown point

44.850, -90.356

Lift-off point

44.905, -90.304

Record number

2505151621-01

36 damage points were recorded along this path by NWS ARX and NWS GRB, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 120 mph.

• 10 transmission line poles snapped, poles were 10 years old.
• Home weather station measured 103 mph.
• Inflow into tornado per aerial analysis of track.
• Downburst on right flank of tornado.

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

During the afternoon hours on May 15th, a developing complex of embedded supercell thunderstorms moved eastward into western Wisconsin. As they continued to intensify, they resulted in widespread hail of up to two inches in diameter across much of western Wisconsin and four tornadoes in Clark County. The strongest of these tornadoes was an EF-2 near Colby, Wisconsin where numerous power poles were downed and one home sustained significant damage to its roof and attached garage.

Showers and thunderstorms developed ahead of an occluded front Thursday afternoon (5/15) across western Wisconsin. Storms tracked through the area during the late afternoon and early evening hours. The strongest storms produced 3 tornadoes, damaging winds, and large hail up to golf ball size across central and north-central Wisconsin.

This tornado touched down southeast of Loyal and tracked to the east-northeast, damaging one residence in addition to trees and powerlines before quickly dissipating.

This strong tornado developed in fields west of Unity before tracking northeast toward Colby. As it moved through rural areas of northeastern Clark County, it damaged multiple farm outbuildings, trees, numerous power poles, and a home. NWS Storm Survey indicated EF2 damage to this home as the majority of its roof was removed with the attached garage heavily damaged. The tornado continued into the southeastern edge of Colby where multiple outbuildings, a home, and a car dealership sustained damage. The tornado moved into Marathon County before it quickly dissipated.

A tornado developed in fields west of Unity in Clark County (NWS La Crosse warning area) at 5:21 pm CDT before tracking northeast toward Colby. The tornado moved through rural areas of northeastern Clark County, damaging multiple farm outbuildings, trees, power poles, and a home before crossing Highway 13 into western Marathon County at 5:27 pm CDT. The tornado tracked through the southeastern edge of Colby damaging another home, multiple outbuildings, power poles, and a car dealership before dissipating at 5:28 pm CDT. Total path length is estimated to be 4.81 miles long, with a width of 230 yards. Peak wind estimated to be around 120 mph.

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

15 minutes of warning. NWS ARX issued a tornado warning for this county at 22:06 UTC, 15 minutes before the tornado touched down, in force until 22:45 UTC.

The county was under a tornado watch, issued at 17:49 UTC and running to 23:32 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 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 19:27 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.

Medford (MDZ), 25 km from the path, in the two hours either side.

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

The La Crosse radar (KARX), 136 km away, was scanning. The volume nearest the touchdown began at 22:18 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 2025 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

34 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.