NASA image shows extensive ice coverage of the Great Lakes
Monday, March 3, 2014, 1:17 PM -
With bitterly cold temperatures dominating much of this winter, it shouldn't come as a surprise that the ice coverage on the Great Lakes is currently well above average.
Scientists say the ice appears to have started building as early as late November.
"According to the National Oceanic and Atmospheric Administration (NOAA) Great Lakes Environmental Research Laboratory (GLERL), ice cover on North America’s Great Lakes peaked at 88.42% on February 12-13 – a percentage not recorded since 1994," NASA says. "The ice extent has surpassed 80 per cent just five times in four decades. The average maximum ice extent since 1973 is just over 50 per cent."
Last year, ice covered about 38 per cent of the Great Lakes, which was a dramatic jump from 13 per cent in 2011-2012.
"The extreme freezing of the lakes is an unusual sight for residents, and has brought tourists flocking to certain locations, such as the Apostle Islands National Lakeshore, where Lake Superior’s thick ice has thousands trekking about one mile across the lake to visit spectacular frozen ice caves," NASA says.
The extensive ice coverage however, interferes with marine commerce, boating and fishing, all of which depend on navigable waterways.
"It also closes the lakes to migratory birds which flock here in the winter time," adds NASA.
WHAT'S RESPONSIBLE FOR HIGH ICE COVERAGE?
According to Weather Network meteorologist Dayna Vettese, certain weather conditions play a crucial role in the formation and stability of the ice.
"The best way for ice to form on the lakes is the obvious one, cold temperatures. Calm weather is another one."
Unusually cold temperatures in the first two months of the year, especially in January, are responsible for the high ice coverage.
"Very cold air blowing over the surface of the water removes heat from the water at the surface. When the surface temperature drops to freezing, a thin layer of surface ice begins to form," NASA explains. "Once ice formation begins, persistently cold temperatures, with or without wind, is the major factor in thickening ice."
Vettese says windy, stormy conditions tend to stir up waters, making them turbulent and harder for the thinner ice to build.
Sea ice is important in a lot of direct and indirect ways to meteorology and forecasting. It affects things like temperatures, ocean currents and winds.
"So in any region that is affected by the influence of a nearby lake, ice can have an impact on your local climate," explains Vettese. "It is very difficult to develop lake effect snow when there is ice on the surface of the lake."
When venturing on the ice, police advise to never go alone, wear the proper clothing and carry the appropriate equipment such as a life preserver.