The Rapidan Dam in Minnesota, located near Mankato, is in a precarious state due to recent flooding of the Blue Earth River. According to multiple sources, including the Blue Earth County Sheriff's Office and Xcel Energy, the dam is now in an 'imminent failure condition.'
The flooding has compromised the structural integrity of the dam and caused significant infrastructure damage. As a result, officials have issued evacuation orders for nearby residents out of concern for their safety.
Minnesota Governor Tim Walz has also declared that roughly 40 counties in the state have been impacted by flooding, with some declaring a state of emergency.
The Blue Earth River begins in northern Iowa and meets with the river's west branch in Faribault County, Minnesota. From there, it flows 108 miles north past the cities of Blue Earth, Winnebago, and Vernon Center to Mankato, where it enters the Minnesota River.
The failure of the Rapidan Dam is expected to cause major flooding downstream along the Blue Earth River. The National Weather Service has issued a Flash Flood Warning for areas downstream from the dam until 10:30 a.m. Tuesday.
Rainfall rates between 1 and 2 inches are forecast for Monday evening in east-central Minnesota, which could lead to flash flooding due to recent rainfall and flooding.
In addition to the Rapidan Dam failure, other areas in the Upper Midwest and northern Plains have experienced record-breaking flooding. At least one person has been killed in South Dakota as a result of the flooding, but no additional details about their identity have been provided by Governor Kristi Noem.
A rail bridge between North Sioux City and Riverside partially collapsed due to the flooding late Sunday night, and several water rescues have been conducted in Iowa's O'Brien County. A train derailed in Lyon County near Alvord.
Multiple river gauges have exceeded their all-time highest crest, including the Big Sioux, Little Sioux, Ocheyedan, and Des Moines rivers. Flooding along the Big Sioux River at Hawarden exceeded its record by 4 feet and caused mandatory evacuations in the town. Power was initially turned off to parts of town that are underwater, but is now safe to drink.
The South Dakota Department of Transportation spent time on Sunday building a berm across both lanes of Interstate 29 to protect North Sioux City and the Dakota Dunes from the flooding.
