Great Lakes Ice Coverage – Winter 2014

This winter, Howe Corporation staff not only experienced the third snowiest January on record, but also witnessed the record-breaking ice coverage of nearby Lake Michigan. The overall average of ice coverage on the Great Lakes this winter was 92 percent, putting winter 2014 in second place for maximum ice coverage after the February1979 record of 95 percent. According to ice-climate scientist Jia Wang of the National Oceanographic and Atmospheric Administration Great Lakes Environmental Research Laboratory (NOAA-GLERL), ice coverage averages this winter were 95 percent for Lake Superior, 92 percent for Lake Michigan, 96 percent for Lakes Huron and Erie, 99 percent for Lake St. Clair, and 62 percent for Lake Ontario. The winter of 1993-1994 came close to this year with 91 percent of Great Lakes ice coverage. The average maximum ice coverage in a typical winter is 51 percent. 

Much of the country experienced record-breaking snow and ice coverage, and inordinately cold weather. What made this winter so extreme? Jia Wang at NOAA attributes these conditions to a neutral El Nino year and the North Atlantic Oscillation. The oscillations cause shifts in high and low pressure systems that affect global weather patterns. In addition, we had an unstable jet stream, which gets its strength from the difference in temperature between subtropic and Arctic air masses. This temperature differential is what drives the winds. As the Arctic region warms, there is less of a temperature differential, causing the jet stream to meander and stay in the same place for a while. The Arctic Jet Stream travelled further south than usual—bringing freezing cold temperatures to the Midwest and Northeast as well as a long winter. Ordinarily, the Arctic Jet Stream stays confined to the northern reaches of the United States. This Arctic warming trend may result in colder and longer winters.

The Great Lakes comprise the largest group of fresh waters in the world, accounting for 94,250 square miles. “Understanding the major effect of ice on the Great Lakes is crucial because it impacts a range of societal benefits provided by the lakes, from hydropower generation to commercial shipping to the fishing industry,” according to NOAA-GLERL. The excessive ice coverage this year has both positive and negative impacts on our environment and economy. The good news is that the ice prevents evaporation resulting in higher lake levels in spring and summer, which will bring some lakes back to normal water levels after a year of historically low water levels. The U.S. Army Corps anticipates Lake Superior to be 13 inches higher than last year. Other Great Lakes may rise as well but they expect Lakes Michigan and Huron to stay below their long-term average. Less evaporation not only provides more sunshine to the states around the Great Lakes, but also colder temperatures and less lake effect snow. Some farmers like the ice coverage because it delays the arrival of spring and helps keep some crops dormant, and limits the freezing of crops early in the growing season.

The ice coverage represents bad news for the shipping industry as it prevents cargo travel from port to port and into shipping lanes. In 1957, there was so much ice on Lake Superior that 100 freighters were trapped in it. (Dwight Boyer, Great Stories of the Great Lakes) This winter a freighter carrying 17,000 tons of coal got stuck in thick ice on Muskegon Lake in Michigan and two subsequent shipments of coal were cancelled. Shipments of iron ore and western coal were drastically affected by the ice that limited cargo moving by ship this winter. So that ships can operate on schedule, the shipping industry is relying on nine of the U.S. Coast Guard’s ships dedicated to breaking up the ice, along with two ice-breaking vessels in Canada. March 25 marked the beginning of the shipping season with the opening of the Soo Locks at Sault Ste. Marie, allowing ships to travel through the Saint Lawrence Seaway and out to the Atlantic Ocean. Hopefully, the captains of these ships will find favorable conditions after a very brutal winter.

Image Credit: NOAA/NASA