Great Lakes water levels are for the most part significantly lower than three years ago (2020), so you’ll likely find more beach to play on this summer.
The graphs below show plots of the current year’s daily lake levels (blue) compared with last year’s levels (black) and last year’s annual average (dark red). The monthly averages are shown as a step plot through the daily averages. Plotted in the background are the coordinated (official) averages (green), record highs (cyan), and record lows (brown) per month as documented here along with additional water level data. Daily levels are from each lake’s master gauge, produced by NOAA/NOS/CO-OPS.
The water level of Lake Superior had a BIG rise this past month due to a fairly rapid, late snowmelt. The 30-day rise of six inches represents a gain of 3.3 TRILLION gallons of water. The lake is 7″ higher than one year ago and is now 13″ higher than the May average level. The level is only 3″ below the highest recorded May water level set in 2019 and is 37″ higher than the lowest May level set in 1926. The dry pattern we are in should bring the level down a bit over the next several weeks.
The water level of Lake Michigan/Huron – one big lake for lake level purposes, because they are joined at the Straits of Mackinac – is up 4″ in the last month. It’s now 3″ lower than one year ago, but 7″ higher than the century average for May. The lake is 26″ below the highest May level set in 2020 and it’s 38″ higher than the lowest May level, which occurred in 1964.
The water level of Lake Erie is unchanged from one month ago. It’s down 1″ from one year ago, but is still 13″ above the May average level. The level is 17″ below the highest May level set in 2020 and it’s 48″ higher than the lowest May level set in 1934.
The water level of Lake Ontario is up 6″ in the last month and up 8″ in the last year. It’s 13″ higher than the May average level, but 17″ lower than the record high level of May 2017. The lake is 49″ above the lowest May level which occurred in 1935.
The water level of Lake St. Clair is up 3″ in the last month, but down 1″ in the last year. It’s also 13″ higher than the average May level. The level is 20″ below the highest May level of 2020, but 42″ above the lowest May level set in 1934.
The rivers that connect the Great Lakes have above average flow. The current flow on the St. Marys River at Sault Ste. Marie is 97,000 cubic feet per second. The average flow for late May is 73,900 cfs. The St. Mary’s River empties into Lake Huron, so the above average flow will partly offset the lower water flow from other rivers that empty into Lakes Michigan and Huron due to the dry conditions we have at this time.
The flow on the St. Clair River at Port Huron is 223,000 cfs, compared to an average flow of 201,000 cfs for late May.
Michigan rivers currently have below average flow. The Grand River in Grand Rapids has a flow of 2,590 cfs, compared to an average flow of 3,580 cfs. That’s 72% of average flow. The Muskegon River at Croton has a flow of 1,480 cfs vs. an average flow of 2,250 cfs. The Kalamazoo River at Comstock has a flow of 609 cfs, compared to an average flow of 957 cfs. The St. Joseph River at Niles has a flow of 3,100 cfs, compared to an average flow of 3,800 cfs.
The Tittawabassee River at Midland MI has a flow of 750 cfs, compared to an average late May flow of 1,520 cfs. The Fox River at Appleton WI has a flow of 1,610 cfs, compared to an average flow of 4,600 cfs.
Flow on Great Lakes rivers will continue to diminish with the dry pattern we have. Again, the water level of Lake Michigan/Huron will not drop that much, because of the inflow from the St. Marys River.