Up to seven inches of rain fell early on Saturday in parts of Detroit and Wayne County, Mich., stranding hundreds of vehicles on flooded freeways and prompting the rescue of about 50 drivers, officials said.
“This isn’t normal here,” said Lt. Michael Shaw, a spokesman for the Michigan State Police. “Every freeway in the county had some level of flooding.”
By 3 p.m. Saturday, the authorities counted about 350 vehicles that had been damaged in the flooding.
“Some suffered some type of wire damage, some had water up to the top of their tires, some had it up to windows, and some were completely submerged,” Lieutenant Shaw said. “A lot of people thought they could make it through the water, but there was just no way.”
Images shared on Twitter showed cars immersed in water and tractor-trailers stuck on freeways.
The last time Southeast Michigan had such flooding was in 2014, after four to six inches of rain fell over a period of four hours, according to the National Weather Service.
There were no injuries reported on Saturday but rescue crews were dispatched to help people trapped in the flooding, Lieutenant Shaw said.
Many basements were flooded, and commuting on Saturday was practically impossible, he said, adding that emergency dispatchers fielded thousands of calls from Friday to Saturday.
Homer Roark, an assistant manager at a Firestone Complete Auto Care in Detroit, said the shop never turns away customers, but on Saturday, they had to turn away 15.
“We’re a maintenance shop and not an engine shop, and there’s so many things that could be wrong with the cars that we had to turn away today,” Mr. Roark said. “I had a lady come in for an oil change, and her car was sopping wet.”
Mr. Roark said he expected more people to come to the shop in coming days, seeking repairs for vehicles that are likely to be permanently damaged.
“There’s just not much we can do when it’s this bad,” he said.
On Saturday, Gov. Gretchen Whitmer declared a state of emergency for Wayne County, which includes Detroit. The order provides local agencies with state resources for recovery and rescue efforts.
Rain is forecast to continue until Friday in the area and was part of a larger unsettled weather pattern in the region.
On Saturday, a tornado watch was issued for parts of Michigan and the National Weather Service in Chicago reported numerous heavy downpours and storms; in Indianapolis, there were reports of scattered thunderstorms and heavy rain.
Ben Gelber, a meteorologist with NBC4 in Columbus, Ohio, said an extraordinary heat dome is reaching into the atmosphere, meaning that when tropical moisture meets it, “everything is largely stuck in place.”
“The best way to describe it is a conveyor belt of moisture that then interacts with the heat associated with the eastern parts of the country,” Mr. Gelber said.
“The fact that this kind of weather pattern is not going to change for the next several days means additional rounds of heavy rainfall,” he added.