Storm Record · Columbia, Dane, Jefferson, Sauk, Waukesha Counties
August 9, 2010: Straight-line wind across five counties
What the National Weather Service recorded
An upper level short wave trough moved rapidly eastward across the Upper Mississippi River Valley and into Wisconsin during the early morning hours of August 9th. The approaching short wave backed low level winds to the south, which brought a moist, unstable air mass into the region with CAPE values of 2000 to 3000 J/kg. A linear mesoscale convective system developed over Nebraska and moved eastward across northern Iowa on the nose of the 30-35 knot low-level winds. This system moved into Wisconsin shortly after 1 am CDT, with the bowing line of storms producing damaging winds along a 10-mile-wide path as it moved rapidly from west to east across South Central and Southeast Wisconsin. The line of thunderstorms extensively damaged trees and downed power lines, including knocking out electrical power to 1,300 Alliant Energy customers in eastern Sauk County and northwest Dane County. Madison Gas and Electric Company reported about 4,000 of their customers lost power on the southwest side of Madison.
Source: NOAA Storm Events Database · episode 44010
Every report, in the Weather Service's words
Where It Hit
| Location | County | Hazard | Size | Report |
|---|---|---|---|---|
| Verona (4 NNE) | Dane | Wind | 75 mph wind | Sheriff deputies reported large trees and power lines blown down from damaging thunderstorm wind gusts estimated at 65 knots (75 mph). |
| Middleton | Dane | Wind | 75 mph wind | Sheriff deputies reported large trees blown down from damaging thunderstorm wind gusts estimated at 65 knots (75 mph). A large tree fell on a house in the 7000 block of Sagebrush Trail, resulting in minor damage. |
| Loganville | Sauk | Wind | 75 mph wind | Sheriff deputies reported extensive trees damage from thunderstorm wind gusts estimated at 65 knots (75 mph). |
| Lodi (3 W) | Columbia | Wind | 75 mph wind | Sheriff deputies reported sporadic damage to large trees from damaging thunderstorm wind gusts estimated at 65 knots (75 mph). |
| Lake Mills (3 SW) | Jefferson | Wind | 75 mph wind | Police officials reported considerable tree damage from thunderstorm wind gusts estimated at 65 knots (75 mph). |
| Dousman | Waukesha | Wind | 64 mph wind | Police officials reported trees and power lines blown down from damaging thunderstorm wind gusts estimated at 56 knots (65 mph). |
| Rio | Columbia | Wind | 64 mph wind | Sheriff deputies reported sporadic tree damage from thunderstorm wind gusts estimated at 56 knots (65 mph). |
Service areas this storm touched