F1 tornado, Busseyville to Ft Atkinson, Wisconsin, August 18, 2005

1. F040 to 72 mph

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

2. F173 to 112 mphthis tornado

   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

F1

Date

August 18, 2005

Touchdown

7:44 PM CDT (00:44 UTC)

Path length

3.0 miles (4.8 km)

Path width

75 yards (69 m)

Deaths

0

Injuries

0

Property damage

$20,000

County

Jefferson County

Touchdown point

42.870, -88.900

Lift-off point

42.850, -88.850

Record number

1149

The largest single-day tornado outbreak in Wisconsin recorded history for south-central and southeast Wisconsin occurred on August 18, 2005. Sixteen tornadoes were documented on this day in south-central and southeast Wisconsin, a new single-day record. A line of supercells developed and pushed across south-central Wisconsin during the afternoon hours, and then pushed east across southeast Wisconsin during the evening hours. Most of the tornadoes were associated with two supercells. One main supercell tracked across Sauk County and then into Columbia, producing one F0 and one F2 tornado. The F2 tornado crossed into Columbia County. Another main supercell produced an F3 tornado that devastated the area north of city of Stoughton (Dane Co.), and a weaker F1 tornado just south of the city of Rockdale (Dane Co.). This supercell then tracked into southwestern Jefferson County a short time later, producing two F0 tornadoes and four F1 tornadoes. The sixteen (16) tornadoes contributed largely to both the new state record of 27 tornadoes on a single day, and 62 tornadoes for a calendar year. In additiion, there were scattered reports of funnel clouds, damaging straight-line, downburst winds, and large hail across south-central and southeast Wisconsin. The total direct damage estimate for the afternoon and evening tornado and severe weather outbreak in south-central and southeast Wisconsin on August 18th was about $36.6 M ($35.7 property and $948 K crop). Additional indirect costs totaled almost $1.9 M, resulting in a total direct and direct cost of about $38.5 M. Synoptically, a surface low pressure system was located over extreme southeast Minnesota early in the afternoon. A warm front extended east southeast from the low with dew points pooling in the lower 70s along it. The surface low moved east into east central Wisconsin by 2100CST that evening. Favorable wind shear associated with the warm front, combined with the strong instability supplied by the heat and humidity, helped to produce numerous tornadic supercells.

This tornado was a continuation of the F3 tornado that tore through the area north of Stoughton (Dane Co.). It crossed into Jefferson County at 1805CST where CTH C starts, about 2.8 miles north-northwest of Busseyville (Jefferson Co.). It traveled east-southeast for about 1.6 miles and dissipated just south of the end of Hartwig Road, about 2.2 miles north-northwest of Busseyville, at 1805 CST. Damage to large tees was noted, as well as some minor crop damage. This portion of the tornado track was rated F1 with estimated wind speeds of 64-97 knots (73-112 mph). The average path width was 50 yards.

The first of five tornadoes in or around Fort Atkinson developed at 1815CST, 5.5 miles west of Fort Atkinson, or near the end of West Grove Rd. It headed southeast and dissipated 5.2 miles west of Fort Atkinson at 1817CST, or about 0.2 mile north-northeast of the intersection of STH 106 and Kreutz Rd. Two mobile homes minor damage, one residential home was damaged and its 3-car garage was destroyed, one farm shed was destroyed, many large trees were uprooted, and minor crop damage was noted. This tornado was rated F0 with estimated wind speeds of 35-63 knots (40-72 mph). Average path width was 20 yards.

The second of five tornadoes in or near Fort Atkinson developed at 1820CST just east of the first tornado, about 5 miles west of Fort Atkinson, or about 0.3 mile north of the end of East Grove Rd. It tracked cyclonically to the southwest, south, and then southeast where it dissipated about 0.4 mile northeast of the intersection of STH 106 and Kreutz Rd at 1823CST (about 5 miles west of Fort Atkinson). A trailer with a truck inside was tipped over, resulting to damage to both. One residential home sustained minor damage, many large large trees were uprooted or twisted, and minor crop damage was noted. This tornado was rated as F1 with estimated wind speeds of 64-97 knots (74-112 mph). Average path width was 25 yards.

The third of five tornadoes in or near Fort Atkinson developed at 1827CST, about 4.1 miles west of Fort Atkinson, or 1.0 mile west-northwest of the intersection of STH 106 and CTH J. It tracked southeast across Burnham Rd. After crossing North Shore Drive, it dissipated in a swamp about 0.4 mile southwest of the intersection of STH 106 and the STH 26 bypass at 1832CST, or about 2.7 miles west-southwest of Fort Atkinson. One residential home sustained minor damage, two shead used for horses sustained roof and siding damage, many large trees were uprooted or twisted, and minor crop damage was noted. This tornado was rated as F1 with estimated wind speeds of 64-97 knots (74-112 mph). The average path width was 30 yards.

The fourth of five tornadoes in or near Fort Atkinson developed at 1837CST about 1.1 mile southwest of Fort Atkinson in a grassy area west of The Fireside Dinner Theater which is on STH 26 Business. This tornado moved due east through the southern part of the city of Fort Atkinson, just missing The Fireside which had some 500 guests inside, and dissipated 1.3 southeast of the city center on STH 12/89 about 0.2 mile south of Fox Hill Rd. Twenty residential homes and 5 businesses sustained minor damage, one business was destroyed, numerous many large trees were uprooted or twisted, some power-lines were damaged, and minor crop damage was noted. As for business losses, a portion of the roof of the Rock River Lanes was peeled back, the Best Western Motel had minor sign and roofing damage, and the Fort Plaza Mini Warehouse was destroyed. This tornado was rated as F1 with estimated wind speeds of 64-97 knots (74-112 mph). The average path width was about 30 yards.

This tornado spun up at 1844CST about 5.6 miles south-southwest of Fort Atkinson, where Grogan Rd. intersects with Vikerman Rd. It tracked east-southeast and damaged a couple farm sheds and damaged farm machinery on 3 farms. Tree damage and some minor crop damage was noted. It dissipated at 1853CST about 5.7 miles south of Fort Atkinson, or about 0.8 mile south-southeast of the intersection of CTH K and McMillen Rd. near a confluent spot on Allen Creek. This tornado was rated F1 with estimated wind speeds of 64-97 knots (74-112 mph). Average path width was 50 yards.

The fifth of five tornadoes in or near Fort Atkinson developed at 1845CST about 3.2 miles southeast of Fort Atkinson near the intersection of CTH M and CTH N (0.3 mile northeast of this intersection). It moved east across CTH N and then quickly dissipated at 1846CST. Several large trees were uprooted, one corn bin was ripped apart, and two other corn bins were damaged. Minor crop damage was noted. This tornado was rated as F0 with estimated wind speeds of 35-63 knots (40-72 mph). Average path width was 30 yards.

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

29 minutes of warning. NWS MKX issued a tornado warning for this county at 00:15 UTC, 29 minutes before the tornado touched down, in force until 01:18 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 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 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.

Janesville/Rock (JVL), 30 km from the path, in the two hours either side.

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

The Milwaukee radar (KMKX), 29 km away, was scanning. The volume nearest the touchdown began at 00:44 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 2005 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

27 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.