Great Lakes Ice Extent, Water Levels and – Update

Bill's Blog

The Ice Extent on the Great Lakes reached 11.2% – tying the lowest ice extent that we had on the Great Lakes since 1973 (in 2002). However, keep in mind that we probably won’t reach maximum ice extent on the Great Lakes until mid-late February or even early March.

Ice extent on Lake Superior is up to 10.2%. Lake Michigan has a 10.4% ice cover – much of that in Green Bay. Lake Huron has the highest extent of the 5 Great Lakes at 15.8%, but Lake St. Clair has a 44.0% ice cover. Lake Erie, the shallowest Great Lake (average depth just 62 feet) and the one that despite being farthest south often has the highest percentage of ice cover.

Historical Maximum Ice Extent on the Great Lakes

Lower than average precipitation continues to help reduce the high water levels of the Western Great Lakes.

The water level of Lake Superior is down 4″ in the last month (that’s a lot for a month) and down 7″ in the last year. The level is 7″ higher than the January average, but it’s 8″ below the highest January level set in 1986. Since Dec. 1, Marquette has had just 59% of average precipitation…S. Ste. Marie has had 61% of average precipitation and Duluth MN has had 66% of average precipitation.

The water level of Lake Michigan/Huron is also 4″ lower than one month ago. It’s also down a healthy 10″ in the past year. The level is still 28″ higher than the January average and 6″ lower than highest January average set in 1987. Since Dec. 1, Grand Rapids has had 88% of average precipitation and Green Bay has had just 51% of average precipitation.

Lake Erie is up one in the last month, but down 9″ year-to-year. The lake is 26″ higher than the January average, but 7″ below the highest January average level of 1987.

Lake Ontario is down 2″ in the last month and is down a whopping 22″ in the last year. The lake is exactly at the January average level, which is 23″ below the highest January level set in 1935.

Lake St. Clair is up 1″ in the last month, but down 11″ in the last year. It’s 30″ higher than the January average level, but it’s also 8″ below the highest January level set in 1986.

International Border Crossing 1/30/21

The above pic. is a screen grab from the webcam at the International Border at Sault Ste. Marie. Only “essential” crossings are permitted right now…you can see only one lane has tracks in the snow.

The rivers that connect the Great Lakes all have above average flow. The St. Clair River has a flow of 236,000 cfs compared to an average flow of 165,000 cfs.


GREAT LAKES NEWS (and a couple items that aren’t Great Lakes, but are pretty neat): Cool pic. of a “wet microburst” over Chicago as seen from a boat on Lake Michigan. Ice balls at Lake Michigan. Epic swim across Lake Michigan. “Perfect” dinosaur print found on a beach. World’s largest ice maze. How does Lake Michigan affect our climate. A group of women went diving in all 5 Great Lakes within 24 hours. Lake-effect cloud “streets” above Lake Superior. Great Lakes cargo update. The deadliest Great Lake. Chicago has the No. 1 and No. 8 largest water treatment plants in the world. More on the history of the water structure of Chicago. Man falls through Lake Michigan ice. Chicago has sinkholes. Another invasive species. Big, green, poop problem. Nearly 1 mile of undeveloped Lake Huron waterfront slated to become a public park. Save the caribou. Shipwreck artifacts.

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