Flash Flooding and Heavy Rain in Wisconsin, August 18 to 19, 2007

Flash flooding occurred in scattered locations between the northwest side of Darlington to the extreme northeast corner of Lafayette County. Just northwest of Darlington, a road was closed due to fast flowing water covering the road to a depth of 1 to 2 feet. Just east of Blanchardville, CTH H was closed due to fast-flowing water covering that road to a depth of 1 to 2 feet. Some mudslides, soil erosion, and crop losses were also noted. At least 20 homes had some water damage to basement contents. WSR-88D Doppler overnight rainfall estimates ranged from around 2 inches over the southern part of the county to 5 to 6 inches over the northern half.

Although general flooding affected all of Sauk County, significant flash flooding affected the west-central part of the county around Limeridge down to Spring Green. Water depths on CTH K, G, S, TS, and STH 154 in the Limeridge to Hill Point area reached 3 to 4 feet. Gravel shoulder washouts occurred and crops across the county were damaged. It was noted that water entered the basements of many homes in the county. Nine homes in Rock Springs were severely damaged, and water came close to 2nd floor of some homes! Elsewhere, 41 had minor damage and 4 had major damage which involved damage to basement walls (total of $250,000 in damage). Two businesses had minor flood damage ($2,000). Livestock losses of $22,000 were reported, and crop losses were estimated at about $3 million for corn and $1 million for soybeans and alfalfa. Winter rye that was cut prior to the heavy rains will be unusable ($300,000). A major washout occurred on Denzer Rd. where it crosses the East Branch Honey Creek. Another major washout on Boot Jack Rd. about 2.5 ESE of Valton. A small section of a dam at Cazenovia was loosened, but held (about $10,000 in damage). All of the excessive rain ultimately resulted in the Baraboo River at Rock Springs reaching major flood status. At this location the river rose to the 18.5 flood stage at 0922CST on August 19th, crested at 21.37 at 0900CST on August 21st, and fell below flood stage at 2348CST on August 24th. At a spotter location 1NNE Reedsburg, 5.11 was measured overnight, and 5.25 was measured in LaValle.

August, 2007, rainfall totals include: 14.73 in Baraboo, 13.42 in La Valle, 16.91 in Prairie du Sac, 15.92 in Reedsburg, and 14.82 at the Lone Rock Airport.

Although general flooding affected all of Dane County, significant flash flooding affected the community areas of Mt. Horeb, Oregon, Sun Prairie, and Dane. At least 798 homes in Dane County sustained water damage to basement contents and/or basement walls, with damage totals of about $3.96 million. Thirteen homes had major water damage and two were destroyed, while 783 had minor damage. At least 10 businesses reported minor water damage totaling about $380,000. Crop losses were an estimated $5 million. Livestock losses were about $200,000, and farm building losses were about $500,000. Additionally, road damages were about $538,000, water control facility damage was about $320,000, public building damage was about $288,000, public utility damage was about $124,000, and other public property damage was about $37,000. Not included in property or crop losses were debris clearance costs of $197,000 and protective measures of $258,000. A bridge on CTH Y just north of Mazomanie was undermined and damaged by the flood waters and will need to be replaced. Water depths on STH 69 south of Verona reached 3 to 4 feet. Several gravel shoulder washouts occurred and crops across the county were damaged. Soil erosion and crop damage was reported. The water level on Lake Mendota rose to within 1 foot of it's record maximum level. The water level on Lake Monona came within 0.02 feet of it's record maxmium level. Rainfall rates were impressive - a spotter near Oregon measured 2.1 of rain between 2000 and 2100CST on August 18th. In Morrisonville, a spotter measured 7.07 overnight through 1700CST on August 19th. Overnight through 0245CST, 4.40 was measured by a coop observer 3NNE Sun Prairie with water overflowing most roads in that area. Also, water was reported in many basements in the Sun Prairie area. A spotter measured 6.39 overnight in DeForest. At a location 1SE Verona, 5.59 fell overnight through 0122CST. The Stoughton coop observer had 6.03 overnight. In Oregon a spotter measured 5.45 overnight. For comparison, locations in Dane County normally receive about 4 to 4.25 inches of rain in the entire month of August.

Flash flooding affected a swath of Jefferson County from the Lake Mills area to the city of Jefferson after 3 to 6 inches of rain fell overnight. Shorewood Road near Lake Mills was closed where a retention pond overflowed and flooded the road with water 2 to 3 feet deep. Most low roads in county had water over them. Bark River Road in Fort Atkinson was closed. Some soil erosion and crop damage was noted in the surrounding countryside. At least 10 homes sustained minor flood damage to basement contents, and at least 3 businesses had minor damage. Some gravel shoulder washouts were also noted. At a location 3.6WNW Lake Mills, 5.23 of rain was measured overnight through 0145CST on August 19th. It was noted that peak rainfall rates at this location reached 2.98 in 2.3 hours. Ultimately , the CoCORaHS observer at this location measured 6.04 by 1000CST on August 19th. A City of Jefferson spotter measured 5.50 overnight. In the extreme southeast corner of the county, a NWS employee measured 3.81 .

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).

Low-end flash flooding affected scattered parts of Walworth County. Areas affected were the city of Lake Geneva, the village of Sharon, the town of Lyons, and the Town of Spring Prairie. Overnight rainfall amounts on top of a nearly saturated ground ranged from around 3 inches over the southern parts of the county to 4 to 6 inches over the northern parts, based on WSR-88D doppler estimates. Water depths on some roads in low spots reached 2 to 4 feet, and significant soil erosion was noted in the surrounding countryside. At least 20 homes sustained minor flood damage to basement contents. Altogether, residential damage was estimated at $31,000. Gravel shoulder washouts on some roads will require an estimated $19,500 to repair. The Sharon Department of Public Works sewer pumps were damaged by flood waters, and repair costs are estimated at $6,200. No major crop losses were reported. At a location 4ENE East Troy, 5.83 was measured overnight.

Flash flooding affected the Mukwanago area after heavy rains of 6.8 inches fell overnight. Water depths on some city strees reached 2 to 4 feet, and significant soil erosion was noted in the surrounding countryside. At least 25 homes sustained minor flood damage to basement contents. Gravel shoulder washouts occurred and crops in the area were damaged. To the west, a spotter at a location .6SE Eagle had 4.76 overnight.

Flash flooding affected a broad swath Racine County from the northwest corner to the city of Racine after 3 to 5 inches of rain fell overnight (WSR-88D doppler radar estimates. Water depths on some roads in low spots reached 3 to 4 feet, and significant soil erosion was noted in the surrounding countryside. At least 40 homes sustained minor flood damage to basement contents, and at least 10 had major damage (total of $300,000). Gravel shoulder washouts occurred ($170,000 damage) and some crops in the area were damaged ($400,000). Ten sod farms had minor to major damage due to flood waters and erosion ($1.5 million in crop losses). All of the excessive rain ultimately resulted in the Root River Canal at Raymond to reach record flood status. At this gage site the river rose to the 9 flood stage at 0352CST on August 19th, crested at 11.66 at 0215CST on August 21st, and fell below flood stage at 0622CST on August 26th. The Fox River at new Munster reached major flood status. At this gage site the river rose to the 10 flood stage at 1127CST on August 19th, crested at 14.96 at 0815CST on August 24st, and remained above flood stage through the end of the month. A spotter at a location 2NE Sturtevant measured 4.8 overnight.

Flash flooding affected a broad swath of Kenosha County from the northwest corner to the city of Kenosha after heavy rains fell overnight on top of a nearly saturated ground. Fast-flowing water depths on some roads in low spots reached 2 to 3 feet, and significant soil erosion was noted in the surrounding countryside, as well as some crop damage. At least 25 homes sustained minor flood damage to basement contents, and at least 5 businesses had major damage. Gravel shoulder washouts occurred and some crops in the area were damaged. Significant street flooding was reported in the city of Paddock Lake, in the Village of Salem, in the Village of Somer, as well as on CTH KR and CTH H. At least 100 homes had flood damage to basement contents. Overnight rainfall amounts, based on WSR-88D Doppler radar estimates, ranged from around 2 inches over the southern part of the county to around 4 inches across the northern parts.

Significant flash flooding affected the northern half of Iowa County, especially in the Avoca and Arena areas. Fast flowing water of 1 to 3 feet was reporte in those two communities and first responders built berms around Avoca. Water depths on STH 133 reached 2 to 4 feet. Sandbagging efforts in Avoca prevented major damage, however 4 homes in Avoca had water in basements. Ten roads in the Civil Town of Arena were closed. The basement of the County Sheriff buidling flooded out with a fair amount of water damage to contents. Several gravel shoulder washouts occurred and crops across the northern part of the county were damaged due to erosion. Overall, at least 20 homes sustained minor flood damage to basement contents. Additionally, a sump pump overflow occurred in the Iowa County Social Services Building in Dodgeville, resulting in minor water damage to basement contents. Rainfall amounts overnight, based on WSR-88D Doppler radar estimates, ranged from 3 to 4 inches over the southeast corner of the county to 8 to 9 inches along the Wisconsin river near Avoca. Unofficially there were reports of 10 inch amounts near Avoca. |

Flash flooding occurred in scattered locations between the northeast corner around Dayton down to the Brodhead area. Fast-flowing water of depths to 1 to 2 feet covered several roads in this area. In the Civil Town of Decatur, CTH F and CTH E were closed. In the Civil Town of Albany, Tin Can road between Zurfluh and CTH EE, CTH X at River Bridge, and River Road were closed. Some mudslides, soil erosion, and crop losses were also noted. At least 100 homes had some water damage to basement contents. WSR-88D Doppler overnight rainfall estimates ranged from around 3 inches over the southwest corner of the county to 5 to 6 inches over the northeast corner.

Urban and small stream flooding occurred across the northern third of Rock County after 3 to 4 inches of rain fell overnight. Water depths on roads reached a foot, especially in the Evansville and Edgerton areas, however no roads were closed. Reports indicated that the flood waters were not fast flowing, nor did they pose a danger to the public. Some crop damage was noted. Overnight rainfall of 6.4 inches were measured by a spotter in Edgerton. Local residents near Badfish Creek, west of Cooksville, noted that this creek flooded and merged with Frog Pond Creek and the water was 3.5 feet deep between the creeks.