| Episode Narrative |
Significant flash flooding affected parts of south-central and southeast Wisconsin during the overnight hours of August 18th into the pre-dawn hours of August 19th, in a roughly 75-mile wide band from the Iowa-Sauk County border through Dane County to Racine and Kenosha Counties. The flash flooding was the result of very heavy overnight rains from August 18th into August 19th, rangning from 4 to 7 inches (roughly one or two summer month's worth of rain in 24-hours). However, WSR-88D Doppler radar rainfall estimates ranged up to 8 to 9 inches in parts of Sauk, Dane, and Iowa County. These rainfall amounts in such a short period of time only occur once in 100 to 200 years. A graphic of WFO MKX's WSR-88D Doppler radar rainfall estimate is attached to the Flash Flood event for Dane County. Many rivers and streams exceeded flood stage by 1 to 5 feet, and some would remain above flood stage through the end of August, 2007, through the first week of September, 2007. Synoptically, a stalled surface frontal boundary stretched from northern Iowa through northern Illinois, while warm, moist air flowed north up and over the boundary. Just north of the surface boundary was a nearly stationary, thunderstorm initiation zone near the Minnesota/Iowa border. The resultant rounds of storms moved southeast across southern Wisconsin and repeatidly traversed over the same areas. Additional severe flash flooding extended northwest into Vernon, Crawford, and La Crosse Counties and northeast portions of the state of Iowa. Refer to StormData events from those areas for related information. |
| Event Narrative |
Significant flash flooding affected the southwest half of Columbia County, especially from the Okee area near Lake Wisconsin/Wisconsin River over to the Lodi area. Several landslides were noted in the Civil Town of West Point area along the Wisconsin River. A pavement washout closed STH 188 in the Civil Town of West Point. Water depths on STH 188 reached 2 to 4 feet. A small pier on Lake Wisconsin was washed out by the fast flowing drainage water coming in fromt the countryside. A private road about 2.5 miles northeast of Harmony Grove had a washout. Gravel shoulder washouts occurred on several other roads ($50,000 damage) and crops across the southwest part of the county were damaged. Fifty-five residential homes sustained minor damage to basement contents, and 2 homes were destroyed by the flood waters. Three businesses sustained minor flood damage.
August, 2007, rainfall totals include: 11.33 at the Arlington Farm, 15.18 in Lodi, and 14.70 7WNW Poynette (near the Wisconsin River). |
