Historic Flash Flooding Strikes Milwaukee After Record Rainfall

In early August 2025, Milwaukee, Wisconsin, experienced unprecedented flash flooding due to record-breaking rainfall. Over a 24-hour period on August 9, some areas received up to 14 inches of rain, potentially setting new state records. This deluge led to widespread flooding, power outages, and significant disruptions across the region.

The National Weather Service reported that the Milwaukee River at Estabrook Park crested at 11.19 feet, surpassing the previous record of 10.48 feet set in July 2010. The Milwaukee Mitchell International Airport recorded 5.74 inches of rain on August 9, marking the city's second-highest single-day rainfall since records began in 1871. The highest recorded was 6.81 inches on August 6, 1986.

The heavy rainfall overwhelmed the city's infrastructure, leading to significant power outages. Approximately 47,000 customers in southeastern Wisconsin were left without electricity. The Milwaukee Fire Department responded to over 600 calls, including water rescues, gas leaks, and electrical hazards. Major roads, including interstates 43, 41, and 94, were submerged, causing substantial traffic disruptions. Milwaukee Mitchell International Airport faced flooding on runways and taxiways, resulting in numerous flight cancellations and delays.

The flooding also led to the cancellation of major events. The final day of the Wisconsin State Fair was called off due to flooded fairgrounds in West Allis. A scheduled performance by Lynyrd Skynyrd was also canceled. Additionally, the USA Triathlon National Championships' Sprint and Paratriathlon events, scheduled for August 10, were canceled due to flooding and damage on the course.

In response to the disaster, Governor Tony Evers declared a state of emergency to facilitate cleanup and recovery efforts. He emphasized the need for a coordinated response and support for affected communities. Milwaukee County Executive David Crowley also declared a county-wide emergency on August 10. On August 13, Governor Evers formally requested federal disaster aid from the Federal Emergency Management Agency (FEMA).

This event is considered a 1,000-year flood for Milwaukee, marking the second-highest recorded rainfall over a two-day period in the city's history. The floods are part of a long-term increasing precipitation trend in southern Wisconsin, which has seen a 17% rise since 1950. The National Weather Service committed to examining the decision to send a flash flood alert to cell phones in the region at about 1 a.m., which local meteorologists had criticized as being made too late.

The unprecedented rainfall not only shattered previous records but also exposed critical weaknesses in Milwaukee's infrastructure and emergency preparedness. As the city grapples with the aftermath, questions arise about the adequacy of existing systems to handle such extreme weather events, which are becoming increasingly frequent due to climate change.

Residents shared harrowing experiences of escaping submerged vehicles and dealing with flooded homes. City officials and meteorologists described the storm as unprecedented, with more rain expected, though not on the same scale. The National Weather Service has begun reviewing the rainfall data, which could officially become Wisconsin’s highest recorded rainfall once verified.

The Milwaukee Metropolitan Sewerage District was forced to let 5.14 billion gallons of untreated wastewater overflow into rivers and Lake Michigan over the course of 78 hours. Officials credited $580 million in previous green infrastructure and flood management construction projects for limiting the amount of flooding.

As Milwaukee continues to recover from this historic flooding, the event serves as a stark reminder of the challenges posed by extreme weather events and the importance of resilient infrastructure and effective emergency preparedness.