Wisconsin Tornado Outbreak of August 2005

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Wisconsin Tornado Outbreak of August 2005
Photograph of Stoughton tornado (via NWS)
Photograph of Stoughton tornado (via NWS)
Date of tornado outbreak: August 18, 2005
Duration1: 8 hours, 40 minutes
Maximum rated tornado2: F3 tornado
Tornadoes caused: 28 confirmed
Damages: $42.537 million
Fatalities: 1
Areas affected: Wisconsin, Minnesota

1Time from first tornado to last tornado
2Most severe tornado damage; see Fujita Scale


The Wisconsin Tornado Outbreak was an outbreak of tornadoes that occurred primarily in southern Wisconsin on August 18, 2005; and another tornado touched down in Minnesota. A total of 27 confirmed tornadoes were reported that day in Wisconsin, the most confirmed tornadoes that have ever occurred in the state in a single day. This broke the previous record of 24 tornadoes set on May 8, 1988, an event also notable as a derecho and for generating a haboob which reached black blizzard intensity and generated its own lightning over portions of southern Wisconsin. The system generating the Stoughton tornado also was accompanied by many reports of significantly severe winds and hail throughout the region.

Confirmed
Total		 Confirmed
F0		 Confirmed
F1		 Confirmed
F2		 Confirmed
F3		 Confirmed
F4		 Confirmed
F5
28 11 14 2 1 0 0

Contents

[edit] Confirmed tornadoes

List of confirmed tornadoes - Sunday, September 18, 2005
F#
Location
County
Coord.
Time (UTC)
Path length
Damage
Minnesota
F0 N of Dexter Mower, MN 43°46′N 92°43′W / 43.77, -92.72 1750 0.1 miles (0.2 km) Damaged a single livestock barn and flattened part of a corn field. Caused $6,000 in damages.
Wisconsin
F0 W of Centerville Trempealeau 44°04′N 91°33′W / 44.07, -91.55 1918 0.1 miles (0.2 km) Remained in a grove of trees and damaged them along its extremely short path. Caused $1,500 in damages.
F1 W of Esofea Vernon 43°38′N 91°02′W / 43.63, -91.03 2046 1.2 miles (1.9 km) 1 Injury One mobile home was destroyed, injuring an occupant. A few outbuildings were destroyed as well. Several other buildings suffered varying degrees of damage, and many trees and power lines were snapped. Caused $150,000 in damages.
F2 W of Liberty Vernon, Richland 43°31′N 90°46′W / 43.52, -90.77 2105 20 miles (32.2 km) 3 Injuries Considerable damage in the village of Viola, every building suffered at least minor damage. Heavy damage to most trees. Caused $3.569 million in damages.
F1 Muscoda area Grant, Richland 43°11′N 90°27′W / 43.18, -90.45 2140 4 miles (6.4 km) One home, which was under construction, was completely destroyed. Damage was sustained to about 10 homes. Many trees and power lines were snapped. Path crossed the Wisconsin River as a waterspout. Caused $245,000 in damages.
F1 Necedah area Monroe, Juneau 30°16′N 89°05′W / 30.26, -89.09 2154 0 miles (0.0 km) 3 homes suffered minor damage and a construction site was destroyed. Significant damage to many trees.
F0 E of Avoca Iowa 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) No damage was reported from this brief tornado.
F1 NE of Clyde Iowa, Sauk 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km)
F1 Spring Green Sauk 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) No real structural damage, however there were many fallen or uprooted trees.
F1 Springville Adams 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) Several mobile homes were damaged.
F2 Bluffview area Sauk, Columbia 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) Many trees down, several buildings damaged and some crops destroyed.
F0 W of Merrimac Sauk 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) Spotted along the Wisconsin River.
F1 NE of Westfield Marquette 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) Many trees down and damage to at least one home.
F0 NE of Lodi Columbia 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) No damage reported from this brief tornado.
F3 Stoughton area Dane, Jefferson 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) 1 death - see section on this tornado.
F0 Dane Dane 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km)
F1 S of Rockdale Dane 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km)
F0 W of Fort Atkinson Jefferson 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) First tornado of same tornado family as Stoughton tornado. Combined damage was minor.
F1 W of Fort Atkinson Jefferson 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) Second tornado of same tornado family as Stoughton tornado.
F1 SW of Fort Atkinson Jefferson 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) Third tornado of same tornado family as Stoughton tornado.
F1 S of Fort Atkinson Jefferson 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) Fourth tornado of same tornado family as Stoughton tornado.
F1 S of Fort Atkinson Jefferson 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km) Fifth tornado of same tornado family as Stoughton tornado.
F0 SE of Fort Atkinson Jefferson 30°16′N 89°05′W / 30.26, -89.09 1737 0 miles (0.0 km)) Sixth and final tornado of same tornado family as Stoughton tornado.

[edit] Stoughton area tornado

Photograph of some damage at Stoughton (NWS)
Photograph of some damage at Stoughton (NWS)

By far the most significant tornado of the day developed at 6:15 p.m. 2.0 miles (3.2 km) north of Oregon near Fitchburg, or approximately 5 miles (8 km) south of Madison proper. This large, intense tornado would track for 20.0 (32.2 km) miles into Jefferson County from Dane County. The unusually long-lived tornado traveled mostly east-southeasterly until just east of Stoughton where it began moving almost due easterly.

It passed through rural subdivisions and farms north of Stoughton at around maximum intensity and width of one-half mile (0.8 km), destroying or very heavily damaging 89 houses, heavily damaging 67 houses, with lighter damage to 84 more. Damages from the tornado totaled to $36.89 million. One person was killed and 23 were injured, three seriously. Debris from the Stoughton area was found as far away as Waukesha and Milwaukee counties (two and three counties to the east). This tornado was rated a high-end F3 on the Fujita scale (an F4 rating was considered for it). Federal disaster assistance was requested but FEMA denied a federal disaster area declaration.

Early estimates of the path length and width appeared to point to the tornado rating F5 in the estimates of some experts. Inspection of the damage and determination that the Jefferson County tornado was separate from the Stoughton tornado as well as downward adjustment of path width led to the F4 and later high end F3 ratings. If the tornado did indeed rate F5, it would have been one of a half-dozen or fewer to occur in Wisconsin during the last 120 years.

Initial reports of portions of the path of tornado expanding to over one and a half miles in diameter over farm and swamp land west of US Highway 51 and possibly a second time when the circulation of the tornado may have been partially over Lake Kegonsa making it difficult or impossible to measure the path width at this point. Also seen was a possible touchdown of a smaller, clockwise-rotating tornado on a shorter, parallel path about 5 km/~3 mi north in the town of Dunn visible as a funnel cloud from the south end of McFarland were never confirmed officially.

The damage pattern in the built-up areas of the tornado path and effects on crops and other plants and soil strongly suggest the existence of several suction vortices within the main tornado funnel and/or evolution into a multi-vortex tornado and back before lifting off the ground.

The tornado frequently changed in size and form and eventually became somewhat rain-wrapped after being highly visible; and finally lifted 2.2 miles (3.5 km) north of Busseyville at 6:21 p.m. after traveling 20.0 miles (32.2 km) in an exceptional 53 minutes of continuous track. Numerous other tornadoes occurred during and after this tornado (seven as part of the tornado family associated with the Stoughton supercell, with the last tornado lifting at 7:53 p.m.. Ft. Atkinson was hit three times.

One death was attributed to this tornado. Loss of life was likely minimized due to the efforts of the NWS, local spotters, and Dane County emergency managers. Tornado warnings were put out well in advance of the developing tornado, and TVS (Tornadic Vortex Signatures which NWS WSR88D doppler radar detects) were seen in the Oregon area in advance of the tornado's approach. Spotters maneuvered to the area of the TVS, and once confirmed, sirens were sounded.

Some confusion was caused due to an F0 Tornado occurring in a similar time frame in Columbia County near Lodi, some mistakenly felt the danger had either passed, or was not threatening them.

The Stoughton tornado struck on the day after a devastating fire at one of the city's largest churches (cause unrelated to severe weather) and was the climax of a two-day spate of severe weather in Southern Wisconsin; the previous day several superbolts of lightning were reported as having done extensive damage at various sites in Madison and other Dane County communities including one incident in which a tree many feet in diameter literally exploded when hit by a bolt apparently from a storm 7-10 miles away and with the sun shining at the location at the time.


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