Lake Ontario Shoreline Status

Conservation Halton Issues a Flood Watch Lake Ontario Shoreline at 10:45 AM on June 5th 2019


The latest information provided by the International Lake Ontario - St. Lawrence River Board (ILOSLRB) indicates that Lake Ontario has remained at its record daily lake level that it first reached on June 2nd. The latest daily mean water level of 75.90 m (IGLD 1985 Datum) is the highest on record for Lake Ontario (greater than the highest daily level observed in 2017) and is approximately 84 cm above the historical average for this time of year. While inflows from Lake Erie are at record levels, Ottawa River flows have dropped in recent days allowing outflows from Lake Ontario to increase concurrently. Further increases in Lake Ontario outflows are expected as conditions downstream permit. Lake Ontario levels may continue to rise gradually over the next several days, but that the rise is likely to be small and highly dependent on precipitation inputs. Most scenarios are forecasting a rise of no more than 5cm above the current record levels, with the potential for a larger rise in level under the wettest scenarios.

Lake Ontario is expected to reach its seasonal peak within the next one to three weeks before it begins to slowly decline and will remain very high for the next several weeks and into the summer months.

All shoreline areas should be considered dangerous during this time. Localized flooding combined with the potential for waves to overtop breakwalls and other shoreline structures continue to make these locations extremely dangerous. Conservation Halton is asking all residents to exercise caution around Lake Ontario shoreline areas and to alert children in your care of these imminent dangers.

This Flood Watch - Lake Ontario Shoreline message will remain in effect until June 19th. Conservation Halton will continue to monitor Lake Ontario wind conditions and lake levels closely and will either terminate this message or issue further updates as necessary.

Additional information is available online through the ILOSLRB website and on Facebook:
Current Conditions:

For further information or questions regarding this message contact:
Ben O’Reilly, Flood Duty Officer
(905) 336-1158 x2258
Robin Ashton
Manager, Marketing Services
905-336-1158 x2248
Note: A Flood Watch is issued when flooding is possible in specific watercourses, municipalities or along shoreline locations. Municipal emergency services and individual landowners in flood prone areas should prepare.


Conservation Halton Flood Terminology

The current terminology was adopted by Conservation Halton, other Conservation Authorities across Ontario and the Ontario Ministry of Natural Resources and Forestry (OMNRF) in February, 2012. The change is to ensure flood messages are consistent and in line with severe weather terminology used by other agencies such as Environment Canada and the Weather Network. The terms were developed by a committee of representatives of Conservation Authorities, Conservation Ontario, the Ministry of Natural Resources and Forestry, Environment Canada, and other agencies
The following is the flood and water safety message terminology used by Conservation Halton:

Conditions are within normal limits. No flooding is expected.


Watershed Conditions Statement:
A general notice of weather conditions that could pose a risk to personal safety or which have the potential to lead to flooding. There are two variations of these:

Watershed Conditions Statement - Water Safety:
High flows, unsafe banks, melting ice, or other factors could be dangerous for recreational users such as anglers, canoeists, hikers, children, pets, and others. Flooding is not expected
Watershed Conditions Statement - 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 and cause ice jams, lakeshore flooding, or erosion.
Flood Watch:
Flooding is possible in specific watercourses or municipalities. Municipalities, emergency services, and individual landowners in flood-prone areas should prepare;
Flood Warning:
Flooding is imminent or already occurring in specific watercourses or municipalities. Municipalities and individuals should take action to deal with flood conditions. This may include road closures and evacuations.