Lake Ontario & St. Lawrence River Flood Information

Current and Forecast Lake Ontario Water Level Information

The federal government and International Lake Ontario – St. Lawrence River Board (ILOSLRB) monitors Lake Ontario levels and provides forecasts for future conditions. This information is available at:

Water Level Conditions & Marine Forecasts

Lake Ontario and St. Lawrence River visit https://ijc.org/en/loslrb/watershed/current-conditions
Kingston real time water levels – 613-544-9264 or visit Fisheries and Oceans Canada water levels page. For water level elevation: height in metres (e.g. 1.32) + 74.2 – 0.036 = 75.48 m water elevation above sea level, Geodetic Survey of Canada (GSC).
Brockville real time water levels – 613-345-0095 or visit Fisheries and Oceans Canada water levels page. For water level elevation: height (in metres) + 73.95 – 0.016 = water elevation above sea level (GSC)
Environment Canada Marine Weather Forecast – https://weather.gc.ca/marine/region_e.html?mapID=11

Lake Ontario St. Lawrence River Board

Website – https://ijc.org/en/loslrb
Facebook Page – https://www.facebook.com/InternationalLakeOntarioStLawrenceRiverBoard
Frequently Asked Questions https://ijc.org/en/loslrb/watershed/faq

Factors that Influence Lake Ontario Water Levels

There are three types of water level fluctuations – long-term, seasonal, short-period, and wind generated waves. These fluctuations are explained at http://www.waterlevels.gc.ca/C&A/fluctuations-eng.html. There are also natural factors that affect water levels, they are also explained at http://www.waterlevels.gc.ca/C&A/natural-factors-eng.html. Cataraqui Conservation Authority does not control Lake Ontario water levels.

Video – Causes of 2017 Lake Ontario – St. Lawrence River Flood – Produced by the International Joint Commission. Recap of 2017 conditions and explanation of how water levels are managed on Lake Ontario and the St. Lawrence River.