Lake Ontario water levels rise, not expected to surpass flooding levels in 2017, 2019

Posted 3 May 2023 at 8:14 am

Press Release, International Lake Ontario-St. Lawrence River Board

Heavy rain in recent days across the Lake Ontario-St. Lawrence River basin has led to rapid increases in Ottawa River flows and rising Lake Ontario water levels.

Lake Ontario levels have been rising at a rate of approximately 2 cm (0.8 in) per day and are expected to reach 75.30 m (247.05 ft)  today (May 2) while levels of the St. Lawrence River at Pointe-Claire (Montreal) have risen above 22.20 m (72.83 ft).

Continued wet weather and runoff from the recent rains may result in flooding of vulnerable areas along the Lake Ontario shoreline as well as downstream along the St. Lawrence River, including Lake St. Louis and Lake St. Pierre.

At this time, the water levels of Lake Ontario and St. Lawrence River are expected to remain below the record-highs observed in 2017 and 2019.

The International Lake Ontario-St. Lawrence River Board is monitoring the situation.  The Lake Ontario outflow into the St. Lawrence River continues to be adjusted in accordance with the Plan 2014 F limit.