A complex of storms moved out of Iowa and into southern and central Wisconsin on August 10th. This complex morphed into a line of strong to severe thunderstorms, which  marched eastward and gained strength as it approached Lake Michigan. Widespread tree damage and power outages were reported.

Thunderstorm Wind in IOWA, WISCONSIN
From 10-AUG-21 15:37:00 to 10-AUG-21 15:47:00 (CST-6)
Location: REWEY
Magnitude: 52.00 EG
Crop damage: 2.00K
Reported by: State Official

Iowa County dispatch reported downed trees near Rewey and Mineral Point.

Thunderstorm Wind in LAFAYETTE, WISCONSIN
From 10-AUG-21 15:39:00 to 10-AUG-21 15:50:00 (CST-6)
Location: BELMONT
Magnitude: 52.00 EG
Property damage: 40.00K
Crop damage: 3.00K
Reported by: State Official

Dispatch reported damage to home caused by a falling tree and a downed tree on Olson Lane, SSE of Mineral Point.

Thunderstorm Wind in SAUK, WISCONSIN
From 10-AUG-21 16:05:00 to 10-AUG-21 16:13:00 (CST-6)
Location: SPRING GREEN
Magnitude: 50.00 EG
Crop damage: 0.50K
Reported by: Public

Small tree branches down in Spring Green.

Thunderstorm Wind in DANE, WISCONSIN
From 10-AUG-21 16:25:00 to 10-AUG-21 17:10:00 (CST-6)
Location: BLACK EARTH
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 10.00K
Reported by: Emergency Manager

Multiple reports of trees and power lines downed across Dane County. Cities impacted were Black Earth, Cross Plains, Middleton, Madison, Oregon, and Cottage Grove.

Thunderstorm Wind in COLUMBIA, WISCONSIN
From 10-AUG-21 16:48:00 to 10-AUG-21 16:55:00 (CST-6)
Location: PORTAGE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind speeds were estimated by trained spotter. Branches were downed and a house was struck by lightning in the area.

Thunderstorm Wind in DODGE, WISCONSIN
From 10-AUG-21 17:20:00 to 10-AUG-21 17:40:00 (CST-6)
Location: PORTLAND
Magnitude: 50.00 EG
Property damage: 8.00K
Crop damage: 1.00K
Reported by: Law Enforcement

Power lines downed in the town of Portland and Beaver Dam. Tree damage on the northeast side of Watertown.

Thunderstorm Wind in WALWORTH, WISCONSIN
From 10-AUG-21 18:00:00 to 10-AUG-21 18:10:00 (CST-6)
Location: PELL LAKE
Magnitude: 52.00 EG
Reported by: Public

Winds were estimated, with reports of power outages in the Broomfield area.

Thunderstorm Wind in MILWAUKEE, WISCONSIN
From 10-AUG-21 18:18:00 to 10-AUG-21 18:35:00 (CST-6)
Location: MILWAUKEE COUNTY ZOO
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Reports of large trees uprooted and large tree limbs of 12 to 15 inches downed in the West Allis, Wauwatosa, and Whitefish Bay areas. Reports of downed power lines in the Whitefish Bay area as well.

Thunderstorm Wind in SHEBOYGAN, WISCONSIN
From 10-AUG-21 18:30:00 to 10-AUG-21 18:40:00 (CST-6)
Location: PARNELL
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 1.00K
Reported by: Law Enforcement

Large tree limbs downed.

Thunderstorm Wind in KENOSHA, WISCONSIN
From 10-AUG-21 18:30:00 to 10-AUG-21 18:40:00 (CST-6)
Location: DOWNTOWN KENOSHA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 1.00K
Reported by: Public

Large tree uprooted near Kenosha.

Thunderstorm Wind in OZAUKEE, WISCONSIN
From 10-AUG-21 18:40:00 to 10-AUG-21 18:50:00 (CST-6)
Location: THIENSVILLE
Magnitude: 52.00 EG
Property damage: 8.00K
Crop damage: 8.00K
Reported by: Emergency Manager

Sporadic downed power lines and old/dead trees downed across southern and eastern portions of Ozaukee County.

Thunderstorm Wind in FOND DU LAC, WISCONSIN
From 10-AUG-21 18:15:00 to 10-AUG-21 18:25:00 (CST-6)
Location: CAMPBELLSPORT
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.50K
Reported by: Public

Large tree limbs downed.

Thunderstorm Wind in WASHINGTON, WISCONSIN
From 10-AUG-21 18:10:00 to 10-AUG-21 18:20:00 (CST-6)
Location: WEST BEND
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 1.00K
Reported by: Public

Ornamental tree uprooted. Small garden shed destroyed near Allentown.

Thunderstorm Wind in WAUKESHA, WISCONSIN
From 10-AUG-21 17:50:00 to 10-AUG-21 18:15:00 (CST-6)
Location: OCONOMOWOC
Magnitude: 67.00 MG
Property damage: 150.00K
Crop damage: 15.00K
Reported by: Public

Numerous reports of a number of large trees snapped and uprooted trees across Waukesha County. Winds were estimated to be upward of 60 mph, with locally higher gusts across the southern portion of the county. Wind measurements near Eagle, WI of 68 to 77 mph were observed. A large tree fell on a house causing significant damage near Eagle, WI. A business marquee sign was knocked over in Waukesha. Hail of three-quarters of an inch was also observed.