The evening of August 13th, a slow moving mesoscale convective complex developed, with a band of intense thunderstorms across Pierce, Pepin, and Eau Claire counties in west central Wisconsin. Between 10 pm and 12 midnight, nearly 5 inches of rain fell in portions of Pierce and Pepin counties, causing significant flash flooding, with mud slides reported near Ella, Wisconsin. This was along County Road N, near the Chippewa River. A local observer in Arkansaw, Wisconsin reported 6.5 inches of rainfall between 10 pm and 130 am. The heaviest rainfall, based on local observers and radar estimates, indicated a band of five to seven inches fell between Esdaile, Plum City, Arkansaw, Durand, and Rock Falls, Wisconsin.

Heavy Rain in PIERCE, WISCONSIN
From 13-AUG-09 21:00:00 to 14-AUG-09 01:00:00 (CST-6)
Location: PLUM CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter measured 5.50 inches of rainfall in a four hour period.

Heavy Rain in PIERCE, WISCONSIN
From 13-AUG-09 22:00:00 to 14-AUG-09 02:00:00 (CST-6)
Location: SALEM
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter measured 4.50 inches of rain in a four hour period.

Heavy Rain in PEPIN, WISCONSIN
From 13-AUG-09 21:00:00 to 14-AUG-09 06:00:00 (CST-6)
Location: ARKANSAW
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A local resident near Arkansaw, Wisconsin measured 7.34 inches of rainfall overnight.

Heavy Rain in EAU CLAIRE, WISCONSIN
From 13-AUG-09 22:00:00 to 14-AUG-09 06:00:00 (CST-6)
Location: LAKE EAU CLAIRE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A local trained observer measured 3.40 inches of rainfall overnight.

Flash Flood in PEPIN, WISCONSIN
From 14-AUG-09 00:30:00 to 14-AUG-09 05:00:00 (CST-6)
Location: ARKANSAW
Flood cause: Heavy Rain
Property damage: 1.00M
Crop damage: 0.00K
Reported by: NWS Storm Survey

A team of NWS employees and local law enforcement officials surveyed an area northwest of Arkansaw, Wisconsin that had flood damage. The storm survey determined that from County Road XX, southeast along County Road Z, several mud slides were confirmed along with a washed out roadway along Arkansas Creek. There were also reports of basement flooding in the town of Arkansaw, Wisconsin. Also, a local observer in Pepin County reported several minor mud slides near Durand.  Local law enforcement officials in Pepin County also reported several roads washed out in Frankfort Township, south of Arkansaw, Wisconsin.
Highway crews repaired the highway along Arkansas Creek which rose more than 15 feet and spread about 100' wide during the height of the storm.

Thunderstorm Wind in PIERCE, WISCONSIN
From 13-AUG-09 19:55:00 to 13-AUG-09 19:55:00 (CST-6)
Location: SNOWS CORNER
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The local law enforcement officials reported a large tree blown down along Highway 63, north of Hager City, Wisconsin.

Heavy Rain in PIERCE, WISCONSIN
From 13-AUG-09 19:00:00 to 13-AUG-09 19:55:00 (CST-6)
Location: PRESCOTT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported two inches of rain in less than one hour.

Heavy Rain in PEPIN, WISCONSIN
From 13-AUG-09 21:00:00 to 14-AUG-09 06:00:00 (CST-6)
Location: DURAND
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A local observer measured 6.50 inches of rainfall overnight.

Flash Flood in DUNN, WISCONSIN
From 14-AUG-09 00:15:00 to 14-AUG-09 05:00:00 (CST-6)
Location: EAU GALLE
Flood cause: Heavy Rain
Property damage: 250.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A team of NWS employees and local law enforcement officials surveyed a large area of road damage caused by flash flooding. The survey revealed that county roads along the Missouri and Little Missouri Creek northwest of Eau Galle, Wisconsin, had signs of flood damage and mud slides. Several roads were washed out near Eau Galle, Wisconsin. Also, local law enforcement officials reported a mudslide east of Downsville, Wisconsin along County Road C.

Flash Flood in PIERCE, WISCONSIN
From 13-AUG-09 20:40:00 to 14-AUG-09 00:00:00 (CST-6)
Location: MAIDEN ROCK
Flood cause: Heavy Rain
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The local law enforcement officials received reports of a few roads closed by high water across the southern part of Pierce county, north of Maiden Rock.  Also, a mud slide was reported along Highway A, between State Road 35 and U.S. Highway 10.

Flash Flood in PEPIN, WISCONSIN
From 13-AUG-09 21:50:00 to 14-AUG-09 05:00:00 (CST-6)
Location: ELLA
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The local law enforcment officials reported a mud slide on County Road N, north of Ella, which closed the highway.

Flash Flood in EAU CLAIRE, WISCONSIN
From 13-AUG-09 23:07:00 to 14-AUG-09 01:30:00 (CST-6)
Location: SHAWTOWN
Flood cause: Heavy Rain
Property damage: 150.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The local law enforcement officials reported that Lowes Road, along Lowes Creek, was washed out just outside of Eau Claire, Wisconsin city limits.

Thunderstorm Wind in DUNN, WISCONSIN
From 14-AUG-09 01:00:00 to 14-AUG-09 01:00:00 (CST-6)
Location: RED CEDAR
Magnitude: 60.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A storm survey determined that straight-line winds caused numerous trees to be blown down or uprooted, along with a large trailer flipped over. The damaged area is approximately two miles long and 1/2 mile wide from near the intersection of State Road 85 and 690th Street, north-northeast to near 90th Street.