TRAVERSE CITY — Federal authorities said Great Lakes water levels have crested for the season, save for Lake Superior.
Scientists at the U.S. Army Corps of Engineers announced this week that water levels are now expected to slowly decline on Lakes Michigan, Huron, Erie and Ontario. That comes after Lakes Michigan and Huron — hydrologically the same large, horseshoe-shaped water body divided by the Straits of Mackinac — set another new record for July’s monthly mean water level at 2 inches greater than the prior record set in 1986, according to federal statistics.
That makes seven consecutive months of broken high water level records on Lakes Michigan and Huron. The levels flirted with breaking records much of last year, and came within an inch of doing so twice in 2019.
John Allis, chief of Great Lakes hydraulics and hydrology for USACE Detroit District, said although they expect water levels to decline across most of the Great Lakes, levels still remain extremely high.
Scientists predict water levels on Lake Superior will peak next month before its seasonal decline, while Lakes Michigan and Huron are expected to set another new record for August before dropping back below record levels in September. And that’s even after seasonal decline has already begun.
Other water-watchers also noted current Great Lakes water levels are brimming atypically high along the shorelines.
“Thankfully it appears that we have reached the crest of 2020 in July, but we’re still at a crazy high altitude. I would still call this extremely high levels,” said Mark Breederland, educator with Michigan Sea Grant.
“I’m hoping for some good fall evaporation since Lake Michigan has heated up notably,” he said.
The National Weather Service’s Climate Prediction Center calls for drier than normal weather conditions across the upper Great Lakes during the coming month, but more normal precipitation over the course of the next three months.
Both Breederland and USACE officials said the current continued elevated water levels remain across the Great Lakes, now with the region on the cusp of the fall and winter storm season.
“Fall storms will unfortunately continue to be the driver of shoreline erosion and shoreline change and it appears we’ll still be in very high — but not extremely high — range for quite some time,” Breederland said.
Lake St. Clair, which helps connect Lakes Huron and Erie along with the St. Clair and Detroit rivers, also set a new July monthly mean water level record — beating last year’s record by 3 inches.
Editor's note: This article has been updated to correct Mark Breederland's agency. He works for Michigan Sea Grant. — Aug. 10, 2020