Lake Ontario Shoreline

Current Lake Ontario Shoreline Flood Status: Watershed Conditions Statement – Flood Outlook & Lake Ontario Shoreline

Tuesday May 20, 2025 at 5:00 PM

Conservation Halton advises that Environment Canada and the Ministry of Natural Resources (MNR) Surface Water Monitoring Centre (SWMC) are currently forecasting 30-50 mm of rain over the next few days, beginning late Wednesday morning and continuing through Friday. Elevated water levels in rivers and streams within our jurisdiction can be expected. In addition, although the current Lake Ontario water level is near the long-term average for this time of year, strong easterly winds with gusts up to 50 km/h may produce waves up to 1.5 m along shoreline areas that could exceed established flood thresholds.

Widespread flooding is not anticipated, however, fast flowing water and flooding of low-lying areas, natural floodplains, and areas with poor drainage may be expected.

Conservation Halton is asking all residents and children to keep a safe distance from all watercourses, Lake Ontario shoreline areas, and structures such as bridges, culverts, breakwalls, and dams. Elevated water levels, fast flowing water, and cold water temperatures combined with slippery conditions along stream banks and the potential for waves to overtop breakwalls continue to make these locations extremely dangerous. Please alert children in your care of these imminent dangers.

Conservation Halton will continue to monitor stream, lake, and weather conditions and will issue an update to this Watershed Conditions Statement – Flood Outlook & Lake Ontario Shoreline message as conditions warrant.

This Watershed Conditions Statement – Flood Outlook & Lake Ontario Shoreline will be in effect through Saturday May 24, 2025.

For further information or questions regarding this message contact:

Kyle Slade, Flood Duty Officer
Flood Forecasting & Operations
T: 905-336-1158 ext. 2234
floodadmin@hrca.on.ca

Shelly Datseris
Manager, Communications & Marketing
M: 905-208-0030
sdatseris@hrca.on.ca

Note: A Watershed Conditions Statement – Flood Outlook is issued as an early notice of the potential for flooding based on weather forecast of heavy rain, snowmelt, high wind or other conditions that could lead to high runoff, ice jams, shoreline flooding or erosion.

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Conservation Halton Flood Terminology

The following is the flood and water safety terminology that is used by Conservation Halton, as well as other conservation authorities throughout Ontario, and Ministry of Northern Development, Mines, Natural Resources and Forestry. The terms were developed by a committee of representatives of conservation authorities, Conservation Ontario, the Ministry of Northern Development, Mines, Natural Resources and Forestry and Environment Canada, to ensure alignment with terminology used by other agencies such as the Weather Network.

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Summer Safety Message

Be Aware of Urban Flooding Due to Thunderstorms

Conservation Halton is reminding residents of the dangers that exist near rivers, streams, ponds and lakes due to high intensity thunderstorms. Thunderstorms can develop suddenly during the warmer months and are often accompanied by strong winds, hail, lightning and heavy rain. Residents should be aware that flooding can occur very quickly with passing thunderstorms.

River flooding occurs when rivers and streams rise over their banks and spill into the surrounding land. With high intensity summer thunderstorms, watercourses within Conservation Halton’s jurisdiction can receive large amounts of precipitation over a short period of time, causing water levels to rise with little warning. This type of flooding is more common in urban areas.

Summer Safety Tips – River Flooding

• Stay away from riverbanks and avoid recreational activities in watercourses during storm events, especially thunderstorms.
• Do not drive through, stand, or walk in any moving water. Avoid low-lying areas such as road underpasses and walkways.
• Stay informed on storm events such as thunderstorms through local radio, television, mobile, or other public alerting systems.
• If you are instructed by emergency officials to evacuate due to flooding, do so immediately.
• If you are in danger, call 911 immediately.

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Flood Forecasting and Operations Program

Conservation Halton provides a flood forecasting and operations program to reduce the risk of property damage and loss of life due to flooding. When flooding is possible or about to occur, Conservation Halton issues flood messages to municipal officials, emergency medical services, police, school boards and media. It is the responsibility of municipal officials to warn local residents.

Conservation Halton is responsible for the maintenance and operation of four major flood control dams (Kelso, Hilton Falls, Scotch Block and Mountsberg) and more than 12 kilometers of flood conveyance channels (Sixteen Mile Creek through Milton, Morrison-Wedgewood diversion in Oakville and the Hager-Rambo diversion in Burlington).

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Contacts: