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The ice covering the Great Lakes has retreated slightly, but maybe not for long.
A span of mild weather in the northeast has significantly reduced the amount of ice on the Great Lakes, but researchers anticipate new ice formations after a cold front that is expected to bring more below-zero temperatures into the region.
The Duluth News Tribune reported that the Great Lakes reached their top ice amount at 88 percent back on Feb. 13. Since then, the percentage of ice on all the lakes combined is somewhere around 62 percent.
Sections of the lakes, which hold nearly one-fifth of the freshwater on the world's surface, harden almost every winter. That freezing keeps the Coast Guard's fleet of nine icebreakers busy clearing paths for vessels hauling essential cargo such as heating oil, salt and coal. But over the past four decades, the average ice cover has receded 70 percent, scientists say, probably in part because of climate change.
NASA released images Feb. 19 of the Great Lakes using the Moderate Resolution Imaging Spectroradiometer, which is one of the agency’s Aqua satellite.
Scientists have been speculating that Lake Superior can reach a virtual freeze-over for the first time in 18 years. But the report said that the percentage of ice on the lake dropped from 94 percent to 77.5 percent.
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George Leskevich, a Great Lakes ice forecaster, told the paper that warmer weather and rain contribute to the fewer amount of ice.
The Coast Guard is mandated to keep shipping lanes on the Great Lakes open during the 42-week shipping season, which ended last month. This year, the Coast Guard's Great Lakes ice breaker, Mackinaw, worked overtime to cut through the ice for some 57 U.S.-flag vessels that ply the Great Lakes, laden with raw materials such as iron ore and fluxstone for the steel industry, limestone and cement for the construction industry, coal for power generation, as well as salt, sand and grain.
The vessels transport more than 115 million tons of cargo per year, sustain more than 103,000 jobs and have an economic impact of more than $20 billion, according to the Lake Carriers Association.
"It's probably been the toughest winter we’ve had in about 24 years," Robert Lewis-Manning, president of the Canadian Shipowners’ Association, recently told Global News. "I think the speed at which the lakes froze this year, and not just the lakes but right up to the St. Lawrence River…was very, very early."
The Associated Press contributed to this report