Why are the Great Lakes on the rise? NPR (10/20) During the late summer and early fall, the water level on the Great Lakes usually drops several inches. This year, three of those lakes, Superior, Michigan and Huron, have seen the opposite happen - rising water levels.
Taking a look at Lake Huron's high water level The Sudbury Star (10/18) Lake Huron was, and is now again, way above what is regarded as "chart datum" by the Canadian Coast Guard -- a big change from a couple of summer's ago when we all were complaining about the lake's low level.
Fall like weather arrived in the Great Lakes basin this week. Other than some light precipitation to start the work week, conditions were largely dry across the region. Look for scattered showers at times this weekend accompanied by warmer temperatures. To date in September, the Great Lakes basin as a whole has received above average precipitation.
Water Level Conditions:
Lakes Superior and Michigan-Huron are 9 and 19 inches, respectively, above their levels of a year ago. Lakes St. Clair and Erie are 14 and 7 inches, respectively, above what they were at this time last year, while Lake Ontario is 1 inch above its level from a year ago. Lakes Superior and Michigan-Huron are predicted to fall 1 and 2 inches, respectively over the next month. Lakes St. Clair, Erie, and Ontario are projected to fall 6, 5, and 6 inches, respectively, over the next 30 days.
See the Great Lakes Water Levels web page for more water level information.
Forecasted outflows / channel conditions:
Lake Superiorís outflow through the St. Maryís River is forecasted to be well above average for the month of September. Lake Michigan-Huronís outflow into the St. Clair River and Lake St. Clairís outflow into the Detroit River are predicted to be near average in September. In addition, the outflow of Lake Erie into the Niagara River and Lake Ontarioís outflow into the St. Lawrence River are projected to be above average in September.
Official records are based on monthly average water levels and not daily water levels. Users of the Great Lakes, connecting channels and St. Lawrence River should keep informed of current conditions before undertaking any activities that could be affected by changing water levels. Mariners should utilize navigation charts and refer to current water level readings.