An organized and slow moving low pressure area within a very moist airmass resulted in 9 to 15 inches of rain and historic flash flooding from the west side of Madison to Mazomanie, and south to Belleville. State of Emergencies were declared with hundreds of homes flooded and hundreds of citizens evacuated or stranded in the flood waters.  The flash flooding of streets and creeks on the west side of Madison resulted in the drowning death of one man. The already high levels of the Yahara Chain of Lakes reached record levels for the end of August into early September. This resulted in sustained flooding in sections of the isthmus in Madison and lakeshore areas of Lake Monona and Lake Waubesa. In addition to the historic flash flooding, one EF0 tornado occurred in Delavan in Walworth Co. A couple firefighters were indirectly struck by lightning and suffered minor injuries in Cross Plains. Lightning also was the cause of a house fire near Cross Plains.

Flood in IOWA, WISCONSIN
From 21-AUG-18 13:00:00 to 22-AUG-18 13:00:00 (CST-6)
Location: ARENA
Flood cause: Heavy Rain
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The record flooding of Black Earth Creek caused a rail bridge to fail on Wisconsin & Southern Railroad near Blynn Road east of Arena. Sections of railroad tracks were also washed out. The flooding of Blue Mounds Creek near Arena reached Village Edge Road and Helena Road on the north side of the village. Sandbagging and pumping was employed to protect homes. Highway 14 was inundated and closed by flood waters just west of County Road K due to record flooding of Black Earth and Blue Mounds Creeks.

Flash Flood in DANE, WISCONSIN
From 20-AUG-18 16:15:00 to 20-AUG-18 22:56:00 (CST-6)
Location: SPRINGFIELD CORNERS
Flood cause: Heavy Rain
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Law Enforcement

The widespread flash flooding of creeks and streets in Middleton, Verona, and the west side of Madison resulted in dozens of flooded or stranded vehicles, over 50 water rescues, and hundreds of citizens stranded in place. One drowning death occurred when a man attempted to escape the flood waters by exiting his vehicle. Many city streets were closed including major thoroughfares. 70 residences in the village of Shorewood Hills suffered water damage with 15 families displaced from their homes. Basement flooding was common in Madison and suburbs to the west and south. Water rescues were also executed just west of Verona on County Highway PD due to flash flooding of the Sugar River. Some rural roads south of Madison and Verona were closed due to flooding from the Sugar River or other creeks, including portions of highway 69. Flood waters at Morey Airport in Middleton tipped over a 500 gallon tank of gasoline and a 1,000 gallon tank of jet fuel. The gas tank leaked and was contained by a containment berm.

Flood in GREEN, WISCONSIN
From 22-AUG-18 02:00:00 to 23-AUG-18 09:30:00 (CST-6)
Location: ALBANY
Flood cause: Heavy Rain
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Emergency Manager

The Sugar River nearly reached moderate flood stage, cresting at 12.91 feet in Albany during the early evening of August 22nd. In the Attica area, 23 cows were rescued from flooded waters due to the flooding of the Sugar River during the early morning hours. Floodwaters caused basement flooding of some homes along South Water Street and a few businesses on North Water Street in downtown Albany. Floodwaters affected the back yards of a few homes along South Mill Street. Floodwaters affected Village Park.

Flash Flood in DANE, WISCONSIN
From 20-AUG-18 20:00:00 to 20-AUG-18 22:56:00 (CST-6)
Location: SPRINGFIELD CORNERS
Flood cause: Heavy Rain
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Law Enforcement

Historic flash flooding of Black Earth Creek and various creeks and low lying areas of western Dane County caused significant flooding impacts. This included hundreds of citizens rescued, evacuated, or stranded, especially along the highway 14 corridor which parallels Black Earth Creek. Homes and businesses in Cross Plains, Black Earth, and Mazomanie were most impacted.  Approximately one half the village of Mazomanie was flooded by Black Earth Creek. 160 homes in Mazomanie were affected while 100 of them experienced water on the 1st floor of the home. 6-12 homes will likely need to be demolished. A bridge was partially washed out on highway 14 near Black Earth, with highway 14 being closed from Middleton to the Iowa County line due to many washouts and high water. Many other roads in western Dane County were closed due to washouts and high water, including southbound 151 near Mount Horeb and large portions of highway 78.  The Black Earth Creek reached record levels of 9.73 feet and 16.6 feet at Black Earth and Mazomanie respectively.

Flood in GREEN, WISCONSIN
From 22-AUG-18 18:37:00 to 26-AUG-18 12:30:00 (CST-6)
Location: BRODHEAD
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 1.00K
Reported by: Emergency Manager

The Sugar River reached moderate flood stage, cresting at 9.29 feet in Brodhead during the early afternoon of August 23rd. There is widespread flooding of lowland and agricultural land in the Brodhead area. Floodwaters cover roads about 6 miles downstream into the Avon Township of Rock County. Floodwaters are over Highway T which is on the border of Green and Rock Counties.

Flood in DANE, WISCONSIN
From 20-AUG-18 22:56:00 to 22-AUG-18 05:00:00 (CST-6)
Location: WAUNAKEE
Flood cause: Heavy Rain
Property damage: 32.80M
Crop damage: 0.00K
Reported by: Law Enforcement

Black Earth Creek crested at 9.73 feet at Black Earth around 2:00 AM on 8/21/18, and at 16.6 feet at Mazomanie around 7:00 AM. The Sugar River and many other creeks and low lying areas continued to flood. The historic flooding resulted in hundreds of citizens rescued, evacuated, or stranded, especially along the highway 14 corridor which parallels Black Earth Creek and then continues into Middleton and Madison. Homes and businesses in Cross Plains, Black Earth, Mazomanie, Middleton, and the west side of Madison were most impacted. Overall, Dane County had 380 homes with affected damage, 857 homes with minor damage, 302 homes with major damage, and 5 homes destroyed. 27 businesses had minor damage and 17 suffered major damage.
A bridge was partially washed out on highway 14 near Black Earth, with highway 14 being closed from Middleton to the Iowa County line due to many washouts and high water. Many other roads in western Dane County were closed due to washouts and high water, including southbound 151 near Mount Horeb and large portions of highway 78. 5000 feet of railroad tracks on the Wisconsin & Southern Railroad were washed out between Mazomanie and Madison.

Flood in ROCK, WISCONSIN
From 22-AUG-18 22:00:00 to 26-AUG-18 16:00:00 (CST-6)
Location: AVON
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 1.00K
Reported by: Emergency Manager

The Sugar River flooded from Green County into Rock County. The Avon Bottoms State Natural Area and Sugar River Park is flooded, including County Road T, which is the border of Green and Rock County.

Lightning in DANE, WISCONSIN
From 20-AUG-18 18:45:00 to 20-AUG-18 20:00:00 (CST-6)
Location: CROSS PLAINS
Property damage: 500.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A home was a complete loss due to a fire from a lightning strike.

Flood in DANE, WISCONSIN
From 21-AUG-18 12:00:00 to 22-AUG-18 21:00:00 (CST-6)
Location: BELLEVILLE
Flood cause: Heavy Rain
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Law Enforcement

The Sugar River rose rapidly in Belleville and flooded Belleville Communitiy Park and some neighborhoods. Nine families were evacuated from the east side of the town. The highway 69 bridge was closed and highway 92 was closed between River St. and County Road PB due to high water from the Sugar River.

Flood in DANE, WISCONSIN
From 23-AUG-18 10:00:00 to 31-AUG-18 23:59:00 (CST-6)
Location: CAMP RANDALL STADIUM
Flood cause: Heavy Rain
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Emergency Manager

Sections of the isthmus in Madison, including many streets,  experienced sustained flooding due to record high water levels on Lake Mendota and Lake Monona. Much of the flooding was near the Yahara River which connects Lake Mendota to Lake Monona. Additional flooding occurred in lakeshore areas of Lake Mendota, Lake Monona, and Lake Waubesa. Thousands of sandbags were deployed to prevent flood damages. Streets, bike paths, parks, boat launches and piers were closed in the isthmus and other areas in the Yahara Chain of Lakes. This overall flooding continued through the end of August and into early September.

Tornado in WALWORTH, WISCONSIN
From 20-AUG-18 19:01:00 to 20-AUG-18 19:05:00 (CST-6)
Location: DELAVAN
Tornado F-scale: EF0
Property damage: 15.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Damage was noted to flags, a large tree limb and metal casing from a US Bank
sign. A small dumpster was also tipped behind the bank. The tornado then tracked to the west northwest through the Wileman Elementary School grounds where numerous large tree limbs were downed. Rubber roofing material on a portion of the school building was lifted and set back in place. The tornado then tracked through residences to the west northwest downing numerous limbs and a rotted/damaged tree. Gutter and roofing damage was noted on one home.

Lightning in DANE, WISCONSIN
From 20-AUG-18 18:00:00 to 20-AUG-18 20:00:00 (CST-6)
Location: CROSS PLAINS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Two firefighters responding to a structure fire were indirectly struck by lightning near Cross Plains. Minor injuries occurred.