Lake Superior Water Levels

Water Levels

  • Average monthly water level: 183.4 metres
  • A low of 182.8 metres elevation in March 2007
  • A high of 183.8 metres in September 1996

Over the past centuries the lake level has fluctuated from 180.6 metres to 183.8 metres based on climate and weather changes. The real control on water levels is the elevation of the St. Mary's Rapids; these rapids form the main control on minimum and maximum lake levels. Factors such as snow melt, precipitation and seasonal temperature drive the annual rise and fall of the lake. Short term factors such as strong winds and storms can create a "seche" which resembles the tides found in the oceans. Elevations during these storm events can differ from one side of the lake to the other by over a metre during these short term weather events. The International Joint Commission regulates the water level on Lake Superior and has a goal of maintaining the 183.4 long time average water level.

Current Water Levels

Department of Fisheries and Oceans (D.F.O.) Canada

Lake Superior water levels- Gauges and Lake Levels (U.S.A.)

Weekly Water Levels on the Great Lakes (Shows the weekly rise or fall from the average of 183.2m)

Changes and Predictions in Water Levels

Graph of Month by Month Water Levels (Shows seasonal variation [D.F.O.])

Great Lakes Environmental Research Laboratory Website

Interactive Water Level Viewers

Water Level Viewer (Pick the camera to view how changing water levels change shorelines.)

Great Lakes Environmental Research Laboratory- Great Lakes Water Levels

Great Lakes Hydro-Climate Dashboard (View historic lake levels and how they have varied over the last century by adjusting the years sliders.)

Lake Superior's Water Budget

Water Levels and Seasonal Changes (images-Minnesota- Sea Grant)

Water Budget- Water added and lost from Lake Superior

The graphs above indicate how Lake Superior's water level fluctuates seasonally. The lake is generally 32cm (1 foot) higher in September than it is in March. Precipitation, winds and temperature are the main inputs that cause the lake level to fluctuate. Lake Superior changes levels less seasonally than the other Great Lakes. The Lake Superior Board of Control is tasked with keeping Lake Superior near it's long term average water level. The Board of Control does not use Lake Superior to raise or lower the other Great Lakes. The lake level has been remarkably consistent over the last several centuries and it has varied by just 1.2 metres. For more information see:

Interesting Links: