Early ice on Superior not necessarily a concern, says researcher

Early ice formation on Lake Superior does not necessarily mean another record ice year is in the forecast, says a scientist who studies ice cover and thickness on the Great Lakes.

Some ice began forming on Lake Superior as early as November 15, more than 10 days earlier than the beginning of last year’s record ice coverage, said George Leshkevich, a physical scientist with Great Lakes Environmental Research Laboratory based in Ann Arbour, Michigan.

“The oscillations up and down seem to be greater in the last few years, but we’ll see what happens this year,” he said.

Although Leshkevich is not a forecaster, he said data has shown in the past that early ice seasons do not necessarily mean record low temperatures or ice coverage.

“The forecasts I have heard are nothing like last year, but the forecasters weren’t expecting the winter we got last year, either,” said Leshkevich.

Leshkevich looks at ice coverage on the lakes as well as the thickness of the ice and shares data with various agencies, including the US and Canadian Coast Guard.

“This helps them in their deployment of ice-breaking resources,” he said.

Ice coverage on the Great Lakes lasted between November 2013 to June 2014, the longest stretch since satellite imagery began mapping conditions in 1974.

Meanwhile, water levels remain above average.

Environment Canada’s most recent data on water levels on Lake Superior shows a delay in the seasonal water level declines for October.

The International Lake Superior Board of Control released figures today showing Lake Superior is 22 centimetres above average going into December and 28 cm above the level recorded a year ago.

Lake Superior's monthly mean water level was 183.67 metres for the month of November, the highest since 1996 at 21 centimetres higher thar the long-term November average.

Another factor that will affect ice creation is the water temperature. Leshkevich said Lake Superior was 4.5 degrees below the long-term average.

“In most places about 98 percent of the lakes were below the long-term averages so it was kind of a cool summer and you get a bit of a jump start to the season,” he said.

The following is a release from the Lake Superior Board of Control:

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The International Lake Superior Board of Control, under authority granted to it by the International Joint Commission (IJC), has set the Lake Superior outflow to 2410 cubic metres per second (m3/s) for the month of December, effective December 3.

The December outflow will be released by discharging about 2298 m3/s through the three hydropower plants and passing most of the remaining flow through the control structure at the head of the St. Marys Rapids.

This past week, the Board began to gradually decrease the gate setting of the control structure in preparation for winter.

The gate setting, which was maintained at an equivalent of approximately five gates open at the start of November, was decreased to approximately three gates open November 25th, and to approximately one gate open November 26.

The gate setting will be further decreased to the equivalent of one-half gate open (four gates open 20 centimetres (cm) each) on December 3.

The one-half gate equivalent setting is the normal winter maximum, and is typically maintained from December through April.

There will be no change to the setting of Gate #1 which supplies water to the channel north of the Fishery Remedial Dike.

The December outflow of 2410 m3/s is 30 m3/s greater than that prescribed by Plan 1977-A.

In April 2014, the Board requested and received approval from the IJC to temporarily deviate from Lake Superior Regulation Plan 1977-A to reduce the risk of unusually high flows expected in the St. Marys Rapids this summer.

To offset some of the effects of releasing flows less than Plan 1977-A from June through September, flows greater than Plan 1977-A were released in May, and again from October through December 2014.

By the beginning of January 2015, the net effect on lake levels resulting from this deviation strategy is expected to be negligible, at which time the Board expects to fully implement Plan 2012, the new regulation plan for Lake Superior.

The monthly mean water level of Lake Superior in November was 183.67 m. This is 21 cm above the long-term (1918-2013) November average and the highest November level since 1996.

For the tenth consecutive month, the net water supplies to Lake Superior were above average again in November.

The level of Lake Superior declined 5 cm last month, which is the average amount the lake declines in November.

The Lake Superior level at the beginning-of-December is 22 cm above average, 28 cm above the level recorded a year ago at this time, and 46 cm above its chart datum level.

The monthly mean water level of Lake Michigan-Huron in November was 176.54 m.

This is 17 cm above the long-term (1918-2013) November average and the highest November level since 1997.

The net water supplies to Lake Michigan-Huron were also above average in November.

The level of Lake Michigan-Huron remained at about the same level last month, while on average the lake declines 5 cm in November.

The level of Lake Michigan-Huron is 20 cm above its long-term average beginning-of-December level, 54 cm higher than it was a year ago, and 54 cm above its chart datum level.

The levels of both lakes Superior and Michigan-Huron are expected to decline in December.

Mr. Jaymie Gadal is the Board Member for Canada. Brigadier General Richard Kaiser is the U.S. Board Member.

For further information, please contact Mr. Jacob Bruxer, Canadian Regulation Representative, International Lake Superior Board of Control, by phone at (613) 938-5862 or by e-mail at [email protected]

Additional information can also be found at the Board’s homepage, or on Facebook.

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(PHOTO: Ships on Lake Superior observed April 23, 2014 near Gros Cap. SooToday.com Staff)