Today’s rain is likely to cause some flooding according to the St. Clair Region Conservation Authority.

Officials expect ponding to occur in low-lying areas as the soil become saturated.

Here’s the authority’s bulletin.

Message: Rain-on-Snow event

•             10 mm to 35 mm in precipitation (snow-water equivalent) over the past week

•             5 mm to 15 mm of rain forecast for today

•             Snowmelt and increased runoff, elevated water levels and chance of minor flooding

Weather Situation:

Winter storms over the past week brought varying amounts of snowfall across the region, with snowpacks measuring snow-water equivalents (SWE) of 10 to 35 mm; areas north of Highway 402 in particular reported heavy snowfall and localized SWE amounts may be higher.

A warm front tracking into southern Ontario is set to bring 5 to 15 mm of rain this morning, with above-freezing temperatures extending into Wednesday.

Risks:

Heavy rainfall this morning will quickly degrade any remaining snowpack and lead to increased runoff into drains and watercourses. Ponding is likely to occur in low-lying areas as soils become saturated, as well as roads if drains are covered or blocked by remaining snow and ice. Water levels are likely to respond quickly to the increased runoff and will be elevated and may lead to minor flooding into natural floodplain areas.

Individuals are reminded to avoid watercourses and flooded areas due to dangerous conditions, slippery banks and cold, swift moving water. Children and pets should be kept away from the water.

The Conservation Authority continues to monitor watershed conditions and will issue advisories to municipalities and media should flood issues arise.

Municipal emergency response staff and road superintendents should monitor local conditions closely.

This message will remain in effect until noon on Wednesday, December 11th, 2024 unless otherwise updated.