National Weather Service United States Department of Commerce

Thunderstorm Downburst Slams Fox Valley

Last updated 9/6/11  9 am

A small cluster of intense thunderstorms produced wind gusts over 70 mph and widespread damage across central and east-central Wisconsin during the morning of September 2, 2011. Thousands of trees and power lines were blown down by the thunderstorm cluster. Numerous buildings were also damaged by fallen trees and the high winds. Power was knocked out to over 60,000 people at the height of the storm. Many thousands were still without power 12 hours after the event.

Here are some of the highest measured thunderstorm wind gusts:

Location Peak Wind
Sherwood (40 ft elevation) 81
Wrightstown 78
Oshkosh (EAA) 74
Appleton 72
Point Beach State Park 65

One of the hardest hit areas during the storm was Appleton. Widespread 70 to 75 mph wind gusts were experienced in the city, with isolated winds estimated at around 95 mph. Damage in the Appleton area alone was $5.3 million.

Below is a radar image at 9:36 AM near the time of strongest winds in the Appleton area. Doppler radar measured winds over 80 mph several hundred feet above the ground near Appleton (circled area on "Velocity" image). Click image for larger view.
Radar image. Click for larger view.