LEVELnews: Great Lakes and St. Lawrence River water levels, February 2025

Lakes Superior, Michigan-Huron, Erie, and Ontario experience dry water supply conditions in January

In January, the Great Lakes Basin experienced the following:

• The mean monthly water level of Lakes Superior, Michigan-Huron, and Ontario were below average. In fact, the levels of Lake Superior and Lake Ontario were their lowest since 2013 and Lake Michigan-Huron had its lowest level since 2014. Lakes St. Clair and Erie had above average water levels.
• All the Great Lakes experienced dry to extremely dry water supply conditions (a combination of the precipitation, evaporation, and runoff).
• All the lakes received much less than average precipitation, with Lake Erie recording less than half of its average for the month.
• The water levels of all lakes except Lake Ontario had close to or greater than average monthly declines. Lake Michigan-Huron had its fifth largest decline on record for January. Lake Ontario did not see a change in water level, though on average it rises 5 cm.

¹ Water levels are referenced to International Great Lakes (Vertical) Datum 1985 (IGLD85). For more information, please visit International Great Lakes Datum Update – Great Lakes Coordinating Committee.

With average water supplies for this time of year, Lake Superior and Michigan-Huron are expected to continue their seasonal water level decline while Lake St. Clair, Erie, and Ontario may have reached their seasonal low point and begin their seasonal rise in the coming months.

Low-lying areas are at risk for accelerated coastline erosion and flooding with the increased possibility of large storms and stronger winds in the winter months. For current information and forecasts, please refer to the sources listed at the end of this newsletter.

The 2024 navigation season is now closed. Read more about it below.

¹ Lake level changes are based on the differences in levels at the beginning of the month, not the monthly average levels.

¹ At the beginning of February, all of the Great Lakes were at least 10 cm above their chart datum level. Chart datum is a reference elevation for each lake that provides more information on the depth of water for safe boat navigation on the lakes. For more information, please visit Low Water Datum – Great Lakes Coordinating Committee.
² Water levels are referenced to International Great Lakes (Vertical) Datum 1985 (IGLD85). For more information, please visit International Great Lakes Datum Update – Great Lakes Coordinating Committee.

Water levels forecast

Lake Superior ended the month below its average water level and is expected to remain so under most water supply conditions.

Lake Michigan-Huron ended the month below its average water level and is expected to remain below average under typical and drier than average water supply conditions.

Lake Erie is expected to approach its average water level if the lake receives average water supplies conditions over the next 6 months.

Like Lake Michigan-Huron, Lake Ontario also ended the month below its average water level. Water levels are expected to remain so under dry or typical water supply conditions. However, wetter than average water supply conditions may result in above average lake levels in the next few months.

For more information on the probable range of water levels, consult the LEVELnews note on projections.

For a graphical representation of recent and forecasted water levels on the Great Lakes, refer to the Canadian Hydrographic Service’s monthly water levels bulletin.

¹ As a percentage of the long-term average (LTA).
² Environment and Climate Change Canada – Canadian Precipitation Analysis System. For more information, please visit: Technical documentation: Regional Deterministic Precipitation Analysis.
³ <5% extremely wet; <25% very wet; <45% wet; 45-55% average; >55% dry; >75% very dry; >95% extremely dry.
⁴ Please refer to the LEVELnews – What is net basin supply for a description of net basin supply.

Note: The information contained in this report is provisional and is subject to change. Data are calculated from the best available observations at the time of posting.

Closing of the 2024 navigation season

January 5, 2025, marked the closing of the Montreal-Lake Ontario section of the binational St. Lawrence Seaway. The last reported ship to clear the Seaway was the Everlast tug with the 400 ft. tank barge the Norman McLeod. This was an upbound transit through Iroquois lock on January 4, 2025. The Seaway is expected to open in late March or early April 2025.

On January 10, 2025, the Welland Canal officially closed for the season, with the Algoma Innovator being the last freighter to transit through the canal.

Flood information

Great Lakes water levels are difficult to predict weeks in advance due to natural variations in weather. To stay informed about Great Lakes water levels and flooding, visit the Ontario flood forecasting and warning program website.

Additional information can also be found on the International Lake Superior Board of Control website and the International Lake Ontario–St. Lawrence River Board website.

Information on current water levels and marine forecasts

Monthly levels: A monthly water level bulletin, produced by Fisheries and Oceans Canada, is available at: Monthly Water Level Bulletin for the Great Lakes and Montréal Harbour. On this page you will find a link to the full bulletin PDF. This publication is intended to complement the information provided by LEVELnews on a monthly basis.

Daily levels: Current daily lake-wide average levels of all the Great Lakes are available at Great Lakes – Daily Water Levels for This Month in Meters. The daily average water level is an average taken from a number of gauges across each lake and is a good indicator of the overall lake level when it is changing relatively rapidly due to recent high precipitation.

Hourly levels: Hourly lake levels from individual gauge sites can be found on the Government of Canada Great Lakes Water Level Gauging Stations website. These levels are useful for determining real-time water levels at a given site, however, it should be noted that they are subject to local, temporary effects on water levels such as wind and waves.

Marine forecasts: A link to current Government of Canada marine forecasts for wave heights for each of the Great Lakes can be found on the Great Lakes water levels and related data website under the “Wave and wind data” heading. Current marine forecasts for Lakes Superior, Huron, Erie and Ontario are available by clicking on the link of the lake in which you are interested. To view a text bulletin of recent wave height forecasts for all of the Great Lakes, click on the “Text bulletin wave height forecasts for the Great Lakes and St. Lawrence River” link.