What are the ranges of lake level changes?
This century, the differences between the record high and low monthly mean lake levels were: Superior 3.8 feet (1.2 meters); Michigan and Huron 6.2 feet (1.9 meters); Erie 6.0 feet (1.8 meters); and Ontario 6.5 feet (2.0 meters). Short-term water level changes are more dramatic and can last minutes or hours. Passing weather systems and wind shifts cause fluctuations in lake level, called seiches, which can raise lake levels from 6 inches to more that 1 foot for several minutes. Storm surges can temporarily raise lake levels several feet on the open coast and 5 feet in bays, for a few hours. At the eastern end of Lake Erie storm surges up to 8 feet have been recorded, along with a similar drop in water level at the opposite end of the lake.
