Report Finds Decades-Long Spike in Storm Damage in Wisconsin

A roadway is flooded in Wauwatosa near Burleigh Street on Aug. 10, 2025. Corrinne Hess/WPR

A recent report from the Wisconsin Policy Forum shows increases in flood damage over the last four decades caused by extreme rain events have led to rising insurance claims.

From 1978 through 1996, there were relatively few flooding events that caused significant damage in the state, according to Federal Flood Insurance Program data collected in the report.

But since 1997, Wisconsin has been hit with a series of events that topped more than $10 million in damages. The biggest spike in claims came during floods in 2008 with over $50 million in damage to federally insured property statewide.

“Each of these spikes was associated with extreme rainstorms, during the worst of which more than 10 inches of rain fell over the course of a few days,” the report states.

Storms on Aug. 9 and 10 dropped nearly a foot of rain in some parts of Milwaukee and surrounding communities. The report suggests that flooding damage from the event may surpass the previous $50 million damage record.

State climate scientists project that over the next 20 years, there will be a substantial increase in days with heavy rain. Policy Forum tesearcher Tyler Byrnes, who authored the report, believes Wisconsinites should prepare for the unexpected.

“These are very unpredictable events,” Byrnes said. “We don’t know when or where they’re going to happen, but we do know that it’s more likely they’re going to see more days of 3 or 5, or even 10 inches of rain over the next couple of decades.”

Byrnes believes flood insurance, which is available for Wisconsinites in and outside of flood prone areas, can help protect people across the state.

Flood insurance is mandatory for many property owners in floodplains designated by the Federal Emergency Management Agency. Homeowners outside floodplains can purchase flood insurance as well, although only 4 percent of property owners nationwide do.

“It might be something that folks want to look at themselves as, you know, ‘I may not be immediately at risk for a flood, but maybe I should look into this,’” Byrnes said.

Heavy storms will likely lead to more public property damage and a greater need for assistance at all levels of government, he added.

“For the state and local government, federal government, just sort of having plans in place — both sort of immediate response plans, but then also plans to deal with the fiscal impact of having to rebuild roads or school buildings or sewers impacted by these floods,” Byrnes said. “It would be wise to think about this as part of their long term financial planning.”

Report: Spikes in storm damage, extreme rain increase need for flood insurance was originally published by Wisconsin Public Radio.