EF0 tornado, Clark to Colby, Wisconsin, June 17, 2024

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

June 17, 2024

Touchdown

8:59 AM CDT (13:59 UTC)

Lifted

9:01 AM CDT (14:01 UTC)

On the ground

2 minutes

Path length

0.8 miles (1.3 km)

Path width

46 yards (42 m)

Deaths

0

Injuries

0

Property damage

$15,000

Crop damage

$5,000

Counties

Clark and Marathon counties

Touchdown point

44.905, -90.316

Lift-off point

44.909, -90.300

Record number

2406170759-01

7 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 EF1. The highest wind the damage implies is 90 mph.

• Small outbuilding collapsed. Construction was nails, with no anchoring.
• Minor Loss of siding on house
• Collapse of garage structure. Doors likely open, minimal/no fastening.
• Upper portion of tree trunk twisted and broken off.

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

During the morning of June 17th, a line of severe storms moved through portions of western and north-central Wisconsin producing wind damage and three weak tornadoes as it moved northeast.

Thunderstorms developed along a semi-stationary front during the mid-morning and tracked northeast along the boundary through the late morning on Monday (6/17) across central and north-central Wisconsin. The strongest storms produced a brief tornado, damaging winds and small hail.

A brief EF-1 tornado touched down in far northern Clark County and produced little damage before moving into southern Taylor County.

A short-lived EF-0 tornado started in the western side of Colby in Clark County before crossing the county line into Marathon County in NWS Green Bay's warning area. Clark County Emergency Management confirmed a garage door was blown in on the west side of a large manufacturing facility on Division Street. Some roof and tree damage was noted in the vicinity of this facility.

A tornado developed on the Clark County (NWS La Crosse warning area) side of Colby at 8:59 am CDT, then tracked northeast and entering Marathon County at 9:00 am CDT. The tornado continued northeast through the south side of Colby and ended in an open field at 9:01 am CDT. Total path length is estimated to be 0.83 miles long, with a width of 46 yards. Peak wind estimated to be around 70 mph.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

The county was under a severe thunderstorm watch, issued at 08:10 UTC and running to 15:00 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 Storm Prediction Center had this point in a Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 12:40 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), 22 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), 139 km away, was scanning. The volume nearest the touchdown began at 13:58 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 2024 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

2 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.