EF1 tornado, Dane, Wisconsin, July 22, 2010

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 22, 2010

Touchdown

4:08 PM CDT (21:08 UTC)

Lifted

4:10 PM CDT (21:10 UTC)

On the ground

2 minutes

Path length

1.5 miles (2.5 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

Property damage

$1,000

Crop damage

$100

County

Dane County

Touchdown point

43.266, -89.522

Lift-off point

43.263, -89.492

Record number

1007221508-01

A stalled frontal boundary combined with a moist and unstable atmosphere and strong wind shear to produce numerous tornadoes and funnel clouds over South Central and Southeast Wisconsin. A series of vorticity maxima moving west to east through the western Great Lakes enhanced isentropic lift, as a strengthening southerly low-level jet interacted with a nearly stationary west to east warm front.

A National Weather Service survey team confirmed a public report of a tornado near the village of Dane. The EF1 tornado developed just west of STH 113, a little north of the intersection with Reppen Road, and moved east-southeast before dissipating near the intersection of Lee Road and County Road Dam. The tornado caused minor crop damage to a corn field, uprooted trees and snapped large branches, as well as brought a power line down along the path, which averaged 20 yards in width. The EF1 estimated wind speed of 90 mph was based on DI 27(TH), DOD3.The exact start location is Lat. 43.26637 Lon. -89.52248. The exact end location is Lat 43.26337 Lon -89.49240.

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

8 minutes of warning. NWS MKX issued a tornado warning for this county at 21:00 UTC, 8 minutes before the tornado touched down, in force until 21:30 UTC.

The county was under a tornado watch, issued at 20:26 UTC and running to 01:21 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 21:02 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.

Middleton (C29), 17 km from the path, in the two hours either side.

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

The Milwaukee radar (KMKX), 84 km away, was scanning. The volume nearest the touchdown began at 21:06 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 2010 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

16 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.