The Great Lakes are at their lowest level in 35 years, and experts say the water levels are likely to drop even more because of the unusually warm winter weather.
Solid ice sheets are only just now spreading over the bays and inlets of Lake Erie — the shallowest of the Great Lakes — which is usually frozen by late December. Without that ice cover, millions of gallons of water are evaporating from the Great Lakes.
Part of that recent ice cover resulted from lake-effect snow at the eastern end of the lakes; Buffalo, New York, received 7 feet of snow last week.
The western Great Lakes states, however, have been warmer and drier than usual, and even heavy snowfall in January and February may not be enough to replenish the water lost, according to Roger Gauthier, a hydrologist with the U.S. Army Corps of Engineers.
Last year, cargo ships were forced to lighten their loads and many boat ramps became inaccessible as water levels on the Great Lakes fell to their lowest point since 1966.
In Lakes Michigan and Huron, the water level has dropped by more than 40 inches since 1997 and remains 14 inches below average. Lake Superior is more than 6 inches below average, Lake Erie is 4 inches below normal, and Lake Ontario is 1 inch below its average level.
The effects have economic consequences. For every inch of water that Lake Michigan loses, a cargo ship must reduce its load by 90 to 115 metric tons, said Helen Brohl, executive director of the U.S. Great Lakes Shipping Association. That means losses between $22,000 and $28,000.