Rivers swollen from days of record-breaking rain topped two dams in Michigan s Midland County this week, flooding neighborhoods with enough brown, muddy water to fill an Olympic-size swimming pool every two seconds. The flooding sent 10,000 residents who had sheltered in place from the coronavirus pandemic scrambling for higher ground.

Parts of the county 140 miles northwest of Detroit are facing 9 feet of flooding as nearly 5 inches of rain fell over 36 hours, the kind of deluge that takes place only once every 25 to 50 years, meteorologist Paul Gross said. The National Weather Service called the disaster extremely dangerous and urged drivers who encounter inundated roads to turn around, dont drown.

By Wednesday, fears mounted that the deluge could infiltrate a Dow chemical plant and endanger a nuclear research reactor. The company confirmed that floodwaters were commingling with on-site containment ponds.

This is unlike anything weve seen in Midland County, Gov. Gretchen Whitmer said at a press conference late Tuesday. If you have a family member or loved one who lives in another part of the state, go there now.

The flooding marked only the latest immediate environmental threat amid the pandemic, which has a global death toll of almost 319,000, with nearly 90,000 lives lost in the United States.