Current Status: Normal

Summer Safety Message: Be Aware of Summer Thunderstorms

Monday June 12, 2023

BURLINGTON – Conservation Halton reminds residents to be aware of flooding risks due to summer thunderstorms.

Thunderstorms can develop suddenly during the warmer months and are often accompanied by strong winds, hail, lightning, and heavy rain.

Flooding from river or stream systems occurs when water levels rise over their banks and spill into the surrounding land.  Many streams within Conservation Halton’s jurisdiction are susceptible to ‘flash’ floods because of the effects of urbanization on the landscape.  This means that large amounts of rainfall over a short period of time, often associated with thunderstorms, can cause water levels in rivers and stream systems to rise with little warning—even in as little as a few minutes.

Although not within the delegated responsibilities of Conservation Authorities, urban flooding, or flooding in urban areas caused by water exceeding municipal drainage and stormwater system capacities, may also occur as a result of a thunderstorm that brings heavy rains in a short amount of time.

Significant rainfall amounts are sometimes associated with thunderstorms or cells within a tropical system, or a hurricane remnant.  The Atlantic Ocean hurricane season typically occurs each year between June 1^st and November 30^th.  Extreme rainfall amounts from tropical or hurricane remnants have been known to reach areas of Southern Ontario, mostly notably Hurricane Hazel in October 1954.

Residents should be aware that flooding can occur very quickly with passing thunderstorms.

• Stay away from riverbanks and avoid recreational activities in watercourses, such as kayaking, fishing or swimming, during and right after 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 weather hazards, 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.

For more information, contact your local Conservation Authority.

• Lake Simcoe Region Conservation Authority (905) 895-1281
• Toronto & Region Conservation Authority (416) 661-6514
• Conservation Halton (905) 336-1158
• Credit Valley Conservation (905) 670-1615
• Central Lake Ontario Conservation Authority (905) 579-0411
• Ganaraska Region Conservation Authority (905) 885-8173
• Nottawasaga Valley Conservation Authority (705) 424-1479
• Kawartha Conservation (705) 328-2271

Learn more about summer weather hazards and safety tips at: https://www.canada.ca/en/environment-climate-change/services/seasonal-weather-hazards/publications/severe-summer.html

About Conservation Halton’s 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 emergency management officials, school boards, police, and EMS as well as the media.  The municipal officials then take action 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 over 12 kilometers of flood conveyance channels (Sixteen Mile Creek through Milton, Morrison-Wedgewood diversion in Oakville and the Hager-Rambo diversion in Burlington).

Conservation Halton is the community based environmental agency that protects, restores, and manages the natural resources in its watershed. The organization has staff that includes ecologists, land use planners, engineers, foresters, and educators, along with a network of volunteers, who are guided by a Board of Directors comprised of municipally elected and appointed citizens. Conservation Halton is recognized for its stewardship of creeks, forests and Niagara Escarpment lands through science-based programs and services.

CONTACTS:

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Current Rivers & Streams Flood Status:

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.

Additional Resources