South Nation Conservation (SNC) is advising people along the section of the St. Lawrence River shoreline under its jurisdiction to be prepared for flooding.
SNC has repeated a statement also made by the International Lake Ontario – St. Lawrence River Board. The board says Lake Ontario’s water levels are above average for this time of year and are likely to continue increasing because of significant rainfall received this past week.
Lake Ontario levels have been rising at a rate of approximately 1 to 1.5 centimetres/0.4 to 0.6 inches per day and have reached 75.32 metres/247 feet. The International Lake Ontario-St. Lawrence River Board reports water levels have risen above 22.25 metres/73 feet at Pointe-Claire.
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 Lac St-Louis and Lac St-Pierre.
At this time, the water levels of Lake Ontario and the St. Lawrence River are expected to remain above long-term average but below the record-highs observed in 2017 and 2019, and below the record high observed in Lake Ontario this same week in 1973 (75.71 metres/248.39 feet).
On May 4, levels were forecasted to continue rising and are expected to reach a seasonal peak in the next couple weeks.
The International Lake Ontario-St. Lawrence River Board is closely monitoring the situation. The Lake Ontario outflow into the St. Lawrence River continues to be adjusted in accordance with Plan 2014 with daily flow adjustments to consider upstream and downstream conditions.
In addition to high Lake Ontario levels, outflows from the Ottawa River and other tributaries into the St. Lawrence River have also increased substantially in the past several days due to the widespread major rainfall.
At this time, the water levels of Lake Ontario and the St. Lawrence River are expected to remain above long-term averages but below the record-highs observed in 2017 and 2019.
Levels in Lake Ontario influence levels in the upper St. Lawrence River, particularly from Kingston to Iroquois, including Maitland, Johnstown, and Cardinal.
Increasing water levels may cause flooding along the shoreline or in low lying areas.
Residents are advised that strong winds may cause waves, further increasing water levels.
Residents are advised to stay away from watercourses where flows are high and where banks might be unstable. Parents are encouraged to explain dangers to children and provide appropriate supervision around all waterbodies.
South Nation Conservation’s flood outlook statement is in effect until May 19, 2023, at 5 p.m. or until a further update is issued.
