The Ganaraska Region Conservation Authority advises high water levels on Lake Ontario will continue for the next several weeks.
Flood Potential: LOW
Issued: May 8, 2026 at 2:30 p.m.
The water level of Lake Ontario is currently 75.34 meters above sea level (masl), which is 33 cm above normal compared to the long term average conditions for May.
- Persistent precipitation this spring has caused Lake Ontario water levels to increase to the 75.30 m mark by the end of April 2026, an increase of 0.76 m since the start of March.
- The average water level in Lake Ontario rose 42 cm over the month of April, compared to the long-term average April rise of 21 cm.
- Since 1960, Lake Ontario has statistically reached, at or above 75.30 m once every three years, or 33% of the years within the period of record. Although significant, reaching a water level of 75.30 m is not unusual.
- The International Lake Ontario-St. Lawrence River Board (the Board) is closely monitoring conditions and frequently adjusting Lake Ontario outflows in accordance with Regulation Plan 2014. The Board has begun applying the maximum outflow rules for Lake Ontario, which are based on the water level at Lake St. Louis, to limit downstream flooding.
- If near-average water supplies are received in the basin, the lake level may reach a seasonal peak between 75.35 m and 75.40 m in May or June. Higher water levels are possible if weather and water supply conditions are wetter than average. Current forecasts indicate that the peak water level of Lake Ontario should remain 50 cm below the record highs of 2017 and 2019.
Heightened risks, while water levels remain above 75.30 masl, include shoreline flooding, beach submersion, and wave-driven erosion along the shoreline of Lake Ontario
This Shoreline Conditions Statement for the Lake Ontario shoreline within the Ganaraska Region will be in effect until Friday, May 29th, 2026, at 12 p.m. Conservation Authority staff will continue to monitor conditions and provide updates as necessary.
Note: A Shoreline Conditions Statement for Flood Outlook is an early notice indicating the potential for lakeshore flooding, erosion or hazardous conditions due to high winds, surges or rising lake levels.
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Should you have any questions or wish to report flooding, please contact the following GRCA staff (listed below) at 905.885.8173.
Mike Smith
Flood Operations Officer
Cory Harris, P.Eng.
Flood Forecasting & Warning Supervisor