Flash Flooding Along Iowa - Wisconsin Border
July 17-18, 2007

During the evening of July 17, 2007, thunderstorms began forming over parts of northeast Iowa and southwest Wisconsin and continued well through the overnight hours dumping nearly 10 inches of rain from far northern Clayton County, Iowa into Crawford and Grant Counties, Wisconsin.  Significant flash flooding developed during the overnight hours in drainage areas.  Mud and rock slides were also common given the steep terrain in that area.

Hardest hit areas included Bagley, Wisconsin and the communities of Marquette and McGregor in Iowa.

In Bagley, WI, the combination of several drainage basins that converge near town and the damming effect of debris build up along area bridges led to a rapid rise in water through much of the town.  This was especially true between Bagley and the nearby River of Lakes subdivision where water backed up into nearby homes and mobile homes as much as 3 to 4 feet high.  Power loss in town also led to sewer backups.  According to local officials about 100 homes had water on the first floor with about 300 homes affected by the sewer problems.  The nearby Jellystone Campground also experienced flash flooding and water backup from a debris blocked bridge.  Many of the roads in western Grant County had mud slides and were closed at times.  Nickel sized hail was also reported with some of these storms.

In Marquette and McGregor, IA, numerous homes were flooded and cars were reported as floating.  Liquid propane gas containers broke loose in some spots.  Mud and rock slides led to the closure or repair of many nearby roads.

In Prairie du Chien, WI damage was not as bad but numerous homes had water in their basements after seven inches of rain fell.

A flash flood watch was in effect for the area that night and flash flood warnings were issued shortly after midnight to alert residents in the region.  The Grant Co., WI sheriff's department began receiving 911-calls around 1:30 a.m. on Wednesday morning July 18th.



Here are some 24-hour rainfall totals ending 7:00 a.m. July 18th...
...IOWA...
MCGREGOR CLAYTON 9.47
MARQUETTE CLAYTON 8.09
ION ALLAMAKEE 4.89
GUTTENBERG DAM 10 CLAYTON 2.57
LITTLEPORT CLAYTON 2.29
GARBER CLAYTON 2.26
ELKADER 6SSW CLAYTON 2.20
 
...WISCONSIN...
PRAIRIE DU CHIEN 1SW CRAWFORD 7.31
PRAIRIE DU CHIEN CRAWFORD 6.52
PRAIRIE DU CHIEN AP AWOS CRAWFORD 5.13
BURTON GRANT 3.52
MILLVILLE GRANT 2.99
LANCASTER 4WSW GRANT 2.60
PLATTEVILLE GRANT 2.44
ROCKVILLE GRANT 2.14
SINSINAWA GRANT 1.82
CUBA CITY 2NW GRANT 0.85
LYNXVILLE DAM 9 CRAWFORD 0.81
BOSCOBEL RAWS GRANT 0.05
BOSCOBEL ASOS GRANT 0.04
STEUBEN CRAWFORD 0.03

Here is a precipitation estimate graphic from the Doppler radar at NWS La Crosse. The red colors depict estimated rainfall that night of over 9 inches.


Photos from the Bagley, WI area (taken by Todd Shea, NOAA/NWS La Crosse.

Debris backup along bridge near Bagley, WI Flood waters in Bagley, WI Flood waters in Bagley, WI
Debris backed up against bridge near Bagley, WI. Standing water in Bagley, WI. Left over flood waters in Bagley, WI
Flood damage in Bagley Damage to a mobile home Debris left over from flood in Bagley, WI
Water damage to a home in Bagley. Notice water line half way up vehicle. Damage to a trailer and deck. Debris left over from flood.
Debris backup along bridge near Bagley, WI Debris backup along bridge near Bagley, WI Mud slide in northeast Iowa
Flash flood damage northwest of Bagley, along County Road X. Debris piled up along bridge near Jellystone Campground northwest of Bagley. One of many mud slides in the area.

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