The damaging storms that swept through Minnesota this week are pushing rivers closer to flood stage across parts of the state.

The Willow River in Pine County, just north of the Twin Cities, was running high enough Wednesday night that it threatened a local dam, prompting the Sheriff’s Office to call for a voluntary evacuation of communities and people living downriver.

Although the U.S. Army Corps of Engineers determined that the dam was sound, water was spilling over its earthen embankments. As a precaution, the Sheriff’s Office notified residents, including 229 living downstream in the small town of Rutledge, that they should be prepared to evacuate. About 9 p.m., the sheriff said that the water was dropping, but that County Road 61 would remain closed through the night.

Tuesday night, after heavy rains and flooding in west-central Minnesota, the Moose Lake wastewater treatment plant began discharging untreated sewage into Moosehead Lake and Moose Horn River. Sewage was still being discharged as of Wednesday evening. The Minnesota Pollution Control Agency estimated that 450 gallons per minute have been released from the wastewater treatment plant.

Monday’s storms dumped more than 9 inches of rain across the north central part of the state, spawned three tornadoes in Minnesota and one in Wisconsin, and pushed some central Minnesota rivers toward flood stage.

The National Weather Service issued flood warnings for stretches of the Mississippi River through Aitkin and Crow Wing counties and for the Rum River and Snake River in Kanabec and southern Mille Lacs counties through Thursday morning.

The Kettle River, which had been rising toward dangerous flood stage near Sandstone, was expected to begin receding by Thursday morning.

Elsewhere in the state, two small communities were tallying the damage from tornadoes that struck Monday afternoon, toppling trees and power lines and damaging or destroying homes and businesses.

Gov. Mark Dayton visited the shaken Meeker County communities of Litchfield and Watkins Wednesday.

“I’m so happy that no lives were lost, no one was seriously injured. That’s almost a miracle, given the severity of the damage,” he said as he toured the battered towns and visited with residents, including dozens of seniors who were evacuated from a Watkins nursing home just before a tornado roared through town.

The sheer number of volunteers of all ages who turned out to help demonstrates “the best of Minnesota spirit,” Dayton said.

Two EF2 tornadoes — with winds up to 135 miles per hour — hit Litchfield and Watkins Monday. Dayton said it is likely that Meeker County will qualify for state disaster aid as it rebuilds.