Flood Status

FLOOD WARNING – Lake Ontario Shoreline

Flood Potential: High
May 30, 2019  3:0PM

The Ganaraska Region Conservation Authority advises that water levels on Lake Ontario have reached 75.88 meters above sea level, which is 82 cm above average and equivalent to the peak water level observed in the 2017 flood event. This Flood Warning was first issued on May 13th and remains in effect for the Lake Ontario shoreline.

Spring flooding on the Ottawa River is declining, which is allowing more water to be released from Lake Ontario while balancing flooding impacts both downstream and upstream. Outflows will continue to be gradually increased as much as possible while maintaining critical flood levels on the St. Lawrence River as prescribed by Regulation Plan 2014. The International Lake Ontario – St. Lawrence River Board predicts that Lake Ontario will exceed the record high water level that was set in 2017 over the next several days. The lake continues to slowly rise at a rate of approximately one centimeter per day. The peak water level for 2019 is expected to occur in the next one to three weeks depending on rainfall amounts, after which it will begin to decline.

Very high inflows from the Niagara River have contributed to persistently high Lake Ontario water levels and high flows on the St. Lawrence River. This means that even when outflows are increased to the maximum, water levels will decline slowly and take several weeks or months to bring them down to within a normal range.

The main concern during high lake levels is shoreline erosion and flooding of low-lying shorelines including dynamic beaches and wetlands along the shore. Shortened beaches, waterfront trails and shoreline protections may be damaged by wave action especially during strong winds from the south.

While this Flood Warning is in effect, shorelines may be slippery with unstable banks and bluffs may be actively eroding. Residents are asked to exercise caution around our shorelines and to alert any children in their care of these dangers.

This Flood Warning for the Lake Ontario shoreline will be in effect through Friday, June 21st, 2019. Conservation Authority staff will continue to monitor 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
Flood Operations Officer

Note: A Flood Warning is issued as notice that flooding is imminent or already occurring in specific watercourses or municipalities.



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.