The Lake Simcoe Region Conservation Authority advises that Environment and Climate Change Canada are forecasting a weather system expected to move through the watershed beginning Tuesday night, March 10, and lasting through Wednesday, March 11. This weather system is expected to bring up to 20-40mm of rain by the end of Wednesday. Local rainfall amounts may be higher in areas that receive thunderstorms. Heavy downpours may cause flash floods and water pooling on roads.
Over the past several days, above zero temperatures have been experienced by the Lake Simcoe watershed, melting a significant amount of snowpack and increasing flows in area watercourses. These above zero temperatures are expected to continue until Wednesday, continuing to melt the remaining snowpack.
There is a possibility for flooding in various low-lying areas of the watershed due to the expected rainfall and melting of the remaining snowpack. Ice breakups have been reported in some parts of the watershed due to weakening ice cover, and ice jams remain a possibility, particularly around bridges, culverts and outlets to Lake Simcoe. Wind gusts associated with the forecast weather system may hasten ice break-up.
Widespread precipitation, warmer temperatures and associated snowmelt coupled with frozen ground conditions will increase the already higher than normal water levels and flows in our rivers and streams. The combination of slippery and unstable banks, higher than normal flows and cold-water temperature will increase already hazardous conditions close to any river, stream or other water bodies, especially in the vicinity of culverts and bridges.
Extreme caution should be exercised around all water bodies. Children and pets should be kept away from all watercourses.
This Flood Watch will be in effect through Friday, March 13, 2026, at 10:30 a.m., or until otherwise updated or cancelled. For further information, contact duty officer Kenneth Cheney at 905-895-1281.