20-foot waves possible on Great Lakes, flooding expected in Metro Detroit

Hani Barghouthi
The Detroit News

Waves as high as 20 feet could be possible on the Great Lakes and flooding occur in parts of southeast Michigan as a multi-day storm system settles into the region, according to the National Weather Service. 

Residents of Metro Detroit could see 4 inches to 6½ inches of rainfall by late Thursday, the weather service forecasted. 

A flood watch is in effect through Thursday for Huron, Saginaw, Tuscola, Sanilac, Shiawassee, Genesee, Lapeer, St. Clair, Livingston, Oakland, Macomb, Washtenaw, Wayne, Lenawee and Monroe counties.

"Greater coverage and intensity of rainfall is expected to occur toward the I-69 corridor overnight before shifting back south early Wednesday," the weather service said. "The peak of the heavy rain event then occurs from mid-morning through afternoon and into Wednesday night.

"Rainfall rates in excess of 1 inch per hour will be capable of (producing) storm totals in the 2 to 4 inch range with locally higher amounts possible across much of Southeast Michigan by Thursday morning."

Early totals Tuesday night included 1.86 inches of rain in Farmington and 1.34 in Bloomfield Hills, according to the weather service website.

Meanwhile, waves of 12-16 feet are expected in the central parts of lakes Huron and Michigan, with some occasionally reaching 20 feet, according to Kevin Kacan, a meteorologist with the National Weather Service in White Lake Township. 

He said it was unlikely for the waves to remain that high by the time they reach shores, estimating they could wash up as high as 10-12 feet.

This lingering end-of-summer storm cell is due to a low-pressure system moving into the region, bringing with it the forecasted precipitation as well as strong winds, Kacan said. 

The National Weather Service has issued a lakeshore flood advisory from Wednesday morning through Thursday in Berrien, Bay, Huron, Tuscola, Sanilac and St. Clair counties, and a beach hazard statement asking residents and visitors to remain out of the water and away from piers until Thursday evening. 

The Detroit Water and Sewerage Department announced Tuesday that it was scheduling staff to work extended hours due to forecasted heavy rain expected after 4 p.m.

The City of Detroit encouraged residents and businesses in a press release Tuesday to follow recommended flooding tips and keep debris and objects away from catch basins and sewer drains.

The Great Lakes Water Authority (GLWA) also announced Tuesday that team members, technicians from power supply partners and contractors would be on-site at the Freud Pump Station over the next two days to diagnose and troubleshoot issues that may arise from power-related issues following GLWA’s recently installed power quality monitors.

The agency added that troubleshooting at the pump station could only be carried out in real-time in the case of flooding. 

In Macomb County, Public Works Office drain maintenance staff cleared debris from major grates, including along I-94 to reduce the risk of freeway flooding.

"As many commuters unfortunately experienced this summer, some portions of freeways in metropolitan Detroit flooded quickly, leaving many of them stranded," Macomb County Public Works Commissioner Candice S. Miller said in a statement. "We’re trying to be proactive by getting out in front of this predicted multi-day rain event that’s expected to bring several inches of rain to the area."

The crew pulled debris Tuesday from a grate at the Rohrbeck Drain, along westbound I-94 near the Roseville-St. Clair Shores border, to ensure flow is not impeded. Another drain maintenance member pulled debris from a grate in the Sterling Relief Drain just east of Van Dyke Avenue in Sterling Heights.

Officials also are urging residents and businesses to clear trash and other debris from the catch basins on their streets.

"Plastic bottles, bags, paper, leaves and other items clog the grates, blocking or severely restricting the flow of stormwater from reaching sewers. That can quickly result in neighborhood streets flooding," Miller said.

Similar storm warnings were issued in Indiana, where the Chicago Tribune reported that a beach hazard statement took effect at 10 a.m. Tuesday, warning of the potential for waves between 12-16 feet high in portions of Lake Michigan along the northwest Indiana coast. 

Staff Writer Mark Hicks contributed.