Message: Possible thunderstorms may cause flash flooding and pooling on roads

Environment and Climate Change Canada is forecasting a risk of thunderstorms this evening that may bring high-intensity rainfall that could cause ponding and increased runoff. Rainfall amounts of 50 mm to 100 mm are possible, with the potential for peak rainfall rates of 50 mm per hour.

Due to the isolated and sporadic nature of these thunderstorms, the ability to predict the amount of rainfall for specific locations is low. Areas in the region that are relatively close may experience rainfall of very different amounts and rates.

Water levels may elevate into natural floodplain areas and low-lying roadways may be impacted. Soils could be saturated from the rain and may contribute to ponding, increased runoff into watercourses, and possible increased erosion and seepage issues. High amounts of rainfall in a short period of time can lead to increased runoff and flash flooding, particularly in urban areas. Local rainfall amounts could be higher due to the isolated nature of thunderstorms.

Individuals are reminded to avoid watercourses and flooded areas due to dangerous conditions, slippery banks and 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. Please continue to monitor active weather alerts from Environment Canada.

This message will remain in effect until 12 p.m. on June 25th, 2025, unless otherwise updated.