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Great Lakes water levels lower than they were this time last year

Lake Michigan
Posted at 3:43 PM, Mar 11, 2021
and last updated 2021-03-11 15:43:32-05

MICHIGAN — Great Lakes water levels this year are tracking below 2020 levels, according to a news release Thursday.

However, Lakes Superior, Michigan, Huron, St. Clair and Erie remain well above long-term average levels, according to U.S. Army Corps of Engineers officials who track and forecast Great Lakes water levels.

Lake Ontario recently fell slightly below long-term average levels.

The February 2021 monthly mean water levels ranged from to seven to 23 inches below water levels from this time last year.

Since November 2020, the Great Lakes basin experienced four consecutive months of below average precipitation.

This, combined with a cold air outbreak during February, led to increased evaporation across the lakes and caused a St. Clair River ice jam to develop.

When ice jams occur, water levels downstream of the restriction decline, while water levels upstream of the restriction rise.

“Drier conditions this winter aided in seasonal declines on all the lakes,” said Chris Warren, Detroit District Watershed Hydrology Branch chief. “However, as water levels begin their seasonal rise, there is still potential for coastal impacts since water levels remain high.”

Late winter and early spring are typical Great Lakes seasonal rise periods because of increased rainfall and runoff.

Even with lower lake levels, some lakes are still well above average and coastal flooding and shoreline erosion are possible, especially during periods of active weather and increased wave action.

The most recent six-month forecast of Great Lakes water levels predicts levels to remain below record high levels, but above average on all lakes except Lake Ontario, which is expected to remain near average levels.