WATERSHED CONDITIONS STATEMENT: FLOOD OUTLOOK - Lake Ontario Flood Watch Cancelled
ISSUED: June 4, 2020
Flood Potential: Low
The Ganaraska Region Conservation Authority advises that water levels on Lake Ontario have peaked and will be declining over the next several months. The current water level is 75.34 meters above sea level (masl), which is down 4 cm from the peak of 75.38 masl that last occurred on May 8th. The Flood Watch which was issued on April 11th is therefore cancelled to reflect the current conditions.
Lake Erie continues to provide record inflows (via the Niagara River) for this time of year and with all the Great Lakes experiencing high water levels it is expected that Lake Ontario will continue to see above average water levels for the time of year even as they continue to decline.
Dry weather is helping to reduce inflows from the surrounding watersheds, while record high outflows are working to gradually bring down the lake levels. So far, the lake level has declined by 4 cm at Cobourg. Continued slow declines in water levels are expected for the next several weeks to months as high flows are released into the St. Lawrence River. High inflows from Lake Erie will prevent any rapid lowering in Lake Ontario levels.
The International Lake Ontario – St. Lawrence River Board (ILOSLRB) predicts the water level will decline by 1 to 3 cm per week and will fall below 75 masl by September with normal amounts of rainfall.
Conservation Authority staff will continue to monitor Lake Ontario conditions and provide updates as necessary. Should you have any questions or wish to report flooding, please contact the following GRCA staff at 905-885-8173.
Mike Smith Cory Harris, P.Eng.
Flood Operations Officer Flood Warning Coordinator
Note: A Flood Watch is issued as notice that flooding is possible in specific watercourses or municipalities. Municipalities, emergency services and individual landowners in flood-prone areas should prepare.
No flood conditions exist.
Level 1 - Water Safety:
High flows, unsafe banks, melting ice or other factors that could be dangerous for recreational users such as anglers, canoeists, hikers, children, pets, etc. Flooding is not expected.
Level 1 - Flood Outlook:
Early notice of the potential for flooding based on weather forecasts calling for heavy rain, snow melt, high wind or other conditions that could lead to high runoff, cause ice jams, lakeshore flooding or erosion.
Level 2 - Flood Watch:
Flooding is possible in specific watercourses or municipalities. Municipalities, emergency services and individual landowners in flood-prone areas should prepare.
Level 3 - Flood Warning:
Flooding is imminent or already occurring in specific water courses or municipalities.