Great Lakes Water Levels, Ice Extent and News

Bill's Blog

The pic. above was sunset at South Haven, Michigan on Sat. 3/20/21 – the first official sunset of the spring. We’re still headed toward our sunniest March ever. Grand Rapids is at 78.45% sun through the first 20 days of the month with another sunny day to follow for Sunday. We’ve had only 0.06″ of precipitation in Grand Rapids so far this month…that’s only about 4% of average. The below average precipitation continues to bring down Great Lakes water levels.

Simply put…right now there is more water leaving the Great Lakes than coming into the Great Lakes. The pic. above isn’t complete, but you get a good view of Lakes Superior, Michigan and Huron. There’s still snow on the ground in most of the U.P. and in the higher elevations of Northern Lower Michigan.

The flow on the St. Clair River, which drains Lake Huron (and Michigan and Superior) is at 235,000 cubic feet per second, compared to an average flow of 186,000 cfs. So, that’s 126% of average flow.

On the other hand, most Michigan Rivers have below average flow: The Grand River in Grand Rapids has a flow of 3,850 cfs (Sat. evening) compared to an average flow for 3/20 of 6,969 cfs. That’s just 55% of average flow. The Kalamazoo River at Comstock has a flow of 805 cfs, compared to an average flow of 1,380 cfs. The St. Joseph River at Niles has a flow of 2,400 cfs, compared to an average flow of 5,260 cfs. The Muskegon River at 2,490 cfs, compared to an average flow of 3,160 cfs.

On the east side of the state, the Tittawabassee River at Midland has a flow of 2,120 cfs, compared to an average flow of 3,180 cfs…and in E. Wisconsin, the Fox River at Oshkosh has a flow of 6,210 cfs, compared to an average flow of 5,990 cfs.

Graph of the Water Level of Lake Superior

The water level of Lake Superior is down 2″ in the last month and down 7″ in the last year (each inch of water on Lake Superior is 550 billion gallons, so 7″ would be a loss of 3.5 trillion gallons. Superior is 6″ above the average March level, but is now 9″ lower than the record high March level set in 1986.

Graph of the Water Level of Lake Michigan-Huron

The water level of Lake Michigan-Huron is down 2″ in the last month and down 11″ in the last year. That’s a huge and welcome drop. The level is still 24″ above the March average level.

Graph of the Water Level of Lake Erie

The water level of Lake Erie is up 1″ in the last month, but it’s down 15 inches in the last year. The lake is still 19″ above the March average level.

Graph of the Water Level of Lake Ontario.

The water level of Lake Ontario is down 2″ in the last month and down 28″ in the last year. Keep in mind that there is some human control over the water level of Lake Ontario because of the Moses-Saunders Dam. Ontario is 8″ BELOW the March average level and is 35″ below the highest March level reached in 1935.

Graph of the Water Level of Lake St. Clair

The water level of Lake St. Clair is down 2″ in the last month and down 11″ in the last year. The lake is still 24″ higher than the average March level.

Great Lakes Ice Extent 3 20 21

Great Lake ice extent continues to shrink, now down to 6.2%. Lake Michigan is down to 5.4%

Here’s the historic (since 1973) Great Lakes annual maximum ice extent. The maximum ice extent for this winter was 45.8% on 2/19. That’s a little below the average maximum of 53.3%, but well above the 19.5% maximum of last winter. You can see a lot of year-year variation and often there is a span of 2-5 years when the maximum ice extent is similar.

The average ice extent for 1997-2021 was 45% and that’s exactly where we were this past winter.

After sunset at South Haven, Michigan 3 20 21

Great Lakes News: Falling Lake Michigan water levels reveal old shipwreck. February icicles at Lake Michigan. As lake levels drop, marinas and roads can reopen. Gull is at least 29 years old.

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