The Army Corps of Engineers does not expect any records of the Great Lakes this year as we enter seasonal peak. Lake Superior’s all-time mark from 2019 will be safe.
Water levels tend to rise until late summer before retreating through the winter period. The trough is reached right before snow runoff occurs in the spring and the cycle repeats. This year was slightly different just to our south. After reaching a record in 2020, Lakes Michigan and Huron actually hit their highest levels of 2021 in January. That has only occurred three times since 1918.
Heavy rainfall and flooding in the Detroit area is not enough to halt the trend, although total precipitation for the region was 25 percent above normal for the month of July. Parts of the Upper Peninsula remain in an “abnormally dry” pattern as classified by the US Drought Monitor.
Looking out six months, the Corps forecasts above average lake levels for four of the five Great Lakes. Ontario is to remain near its long-term mean. The full press release is below.
Even with a return to wetter conditions in late June and July, U.S. Army Corp of Engineers officials expect Great Lakes water levels to remain below 2019 and 2020 levels – when many record highs were set across the lakes.
Late spring and summer are typically when the lakes reach seasonal peaks before beginning seasonal declines in the late summer or early fall. This year, seasonal rises leading up to peak levels were less than average on all the lakes. This is especially true for Lake Michigan-Huron, which experienced its peak monthly mean level for the year in January. This has only occurred three other times (1931, 1958 and 1987) in the coordinated water level period of record (1918-2020).
“Very heavy rainfall occurred across a large portion of the Great Lakes basin in late June and July,” said Detroit District Great Lakes Watershed Hydrology Chief Keith Kompoltowicz. “This significant precipitation led to a rise in Lake Michigan-Huron water levels in July after a several months stretch of stable water level conditions.”
The very wet July led to the total precipitation for the Great Lakes basin to finish the month about 25% higher than average. From June to July, Lake Superior remained near its June level. Lake Michigan-Huron rose three inches, while lakes St. Clair, Erie and Ontario all rose four inches from June to July.
The U.S. Army Corps of Engineers’ most recent six-month forecast, covering months August through January, indicates Great Lakes water levels will remain below record high levels, but above average on all lakes, except Lake Ontario. Lake Ontario’s forecast indicates water levels will remain near average. https://go.usa.gov/xFEWx.