As of 10 a.m. Wednesday, the Sanford Dam has been breached, but has not broken.
The towns of Edenville, Sanford and parts of Midland have been evacuated, according to Selina Tisdale, spokeswoman for the city of Midland.
There have been no reported injuries or fatalities due to the flooding, and no reports of anyone trapped by the high water, Tisdale said Wednesday.
Whitmer said Downtown Midland, a city of 42,000 about 8 miles downstream from the Sanford Dam, faced an especially serious flooding threat.
The evacuations include the towns of Edenville, Sanford and parts of Midland, according to Selina Tisdale, spokeswoman for Midland County.