Snow melt raising flood risk in parts of southern Ontario

Six-year-old Archer Williamson shovels snow over his head as he helps shovel his walk after a massive snowstorm hit Toronto on Monday Jan. 26, 2026. THE CANADIAN PRESS/Frank Gunn

Some communities in southern Ontario are being warned of potential flooding as warmer temperatures bring melting snow and ice after weeks of subzero temperatures.

The Grand River Conservation Authority, which covers a large area including Kitchener, Waterloo, Guelph and Brantford, is under a flood warning until Thursday as officials say melting snow combined with a chance of rain could cause water levels to rise rapidly.

The conservation authority also says ice weakening and breaking up in rivers could lead to ice jams, which block water flow and can cause localized flooding.

The Halton Conservation Authority, which covers Oakville, Burlington and Milton, is warning that flooding can be expected in low-lying areas, natural floodplains and areas where there is poor drainage.

Halton conservation officials say melting snow combined with rain, which is forecast in the region on Wednesday, has historically resulted in significant flooding and ice jams.

Catfish Creek
Conservation Authority, which covers a small area south of London, is also warning of increased water flow as temperatures rise, though flooding is not expected.

All three conservation authorities are asking the public to exercise extreme caution around waterways, especially rivers and creeks where elevated water levels, fast-moving currents and slippery conditions combine to make these areas particularly dangerous.

The safety advisories come after a record-breaking storm in late January blanketed southern Ontario in snow, much of which stuck around as the longest cold stretch in a decade kept the region in a deep freeze.

Last year, a historically snowy February in Ontario and Quebec followed by a sudden rise in temperatures caused flooding in low-lying areas, including many basements.

The Insurance Bureau of Canada said at the time the storm and subsequent flooding caused over $160 million in insured damage.

This report by The Canadian Press was first published Feb. 16, 2026.

Kathryn Mannie, The Canadian Press