F0 tornado, Lake Mills, Wisconsin, June 6, 1999

1. F040 to 72 mphthis tornado

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. F173 to 112 mph

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

3. F2113 to 157 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. F3158 to 206 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. F4207 to 260 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. F5261 to 318 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

F0

Date

June 6, 1999

Touchdown

4:25 PM CDT (21:25 UTC)

Path length

0.1 miles (0.2 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

Property damage

$3,000

County

Jefferson County

Touchdown point

43.080, -88.900

Lift-off point

43.080, -88.900

Record number

1274

A significant change in the upper level pattern to a more southwesterly flow allowed tropical-like moisture to return to southern Wisconsin in conjunction with an upper level shortwave trough. The result was the first severe weather outbreak across southern Wisconsin since May 16, 1999. A series of upper level shorwaves contintued to move through the Great Lakes region during the remainder of the week into the weekend of of June 12-13, 1999. These shortwaves resulted in additional rounds of severe weather across southcentral and southeast Wisconsin. On June 6th, scattered severe storms eventually became orientated in short lines that produced 2 tornadoes, 10 gustnadoes (classified as thunderstorm wind damage), 3 funnel clouds, hail up to the size of golfballs, damaging straight-line downburst winds up to 80 mph, and isolated torrential rainfalls of around 1 inch within 20 to 30 minutes. In Evansville (Rock Co.), 1/2 inch rain fell within 10 minutes along with large hail. In addition, two people were injured by lightning strikes. Otherwise, numerous large trees and power lines were toppled by the powerful thunderstorm winds.A weak (F0) tornado briefly touched down on the northwest side of Lake Mills (the body of water), Jefferson County, uprooting and snapping large trees, but not causing any other damage. Another weak (F1) tornado spun up just southwest of the intersection of Oakdale and Skyline roads northwest of Big Bend (Waukesha Co.), damaging 6 homes (one had major damage), and 2 pole sheds. This Waukesha tornado was on the ground for about 2/10 of a mile, and weakened after it crossed Oakdale Rd. Most interestingly, the number of gustnadoes reported and verified was the greatest in recent memory. A couple of them were captured on video tape. Several of them resulted in tree damage, and all ten were classified as thunderstorm wind damage. Locations of gustnadoes were: 1) Rock county...Orfordville; Walworth County...3NW Darien, 1W Delevan, Millard, and 1NW East Troy; Waukesha County...3.5W Muckwonago, 1WNW North Prairie, and 2 of them 2SW Harland; Washington County...3SW West Bend on Little Cedar Lake. The Little Cedar Lake gustnado actually spun up on the water surface (gustspout?!?!) and then moved onshore, damaging a pier and uprooting a couple trees before disspating. It was observed by a trained spotter. Another trained spotter found themselve briefly inside one of the gustnadoes southwest of Hartland! The fact that so many gustnadoes were plainly visibile can be partially attributed to significant amounts of dust and dirt that were picked up off nearby farm fields. The was made possible by dry weather during the preceeding 3 weeks coupled with late planting (little vegetation) of some fields. Other notable damage reports included: a motorhome was blown onto State Highway 14 near Evansville (Rock Co.), injuring two people; a home in Hebron (Jefferson Co.) was damaged by a wind-toppled tree, while northeast of Hebron a barn was damaged by fallen trees; a pontoon boat was blown 500 feet near Elkhorn (Walworth Co.); a construction trailer west/northwest of North Prairie (Waukesha Co.) was rolled over and damaged by a gustnado; in Brookfield (Waukesha Co.) a construction trailer was damaged after strong thunderstorm winds flipped it over, while elsewhere in Brookfield a toppled tree damaged a home; in Germantown (Washington Co.)... a home had it gutters and shingles damaged while one of its windows was blown in; just west of Claladenio (Racine Co.) a truck was flipped over by strong thunderstorm winds, and a four block area on Milwaukee's west side suffered an intense wet microburst that damaged 14 homes, 17 vehicles, uprooted 100 trees, and knocked over a few power lines.

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

9 minutes of warning. NWS MKX issued a tornado warning for this county at 21:16 UTC, 9 minutes before the tornado touched down, in force until 22:15 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. The outlook in force was issued at 20:19 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.

Watertown (RYV), 17 km from the path, in the two hours either side.

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

The live radar over the trackEvery 1999 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.