Message: Possible thunderstorms may cause flash flooding and pooling on roads
Environment and Climate Change Canada is forecasting a risk of thunderstorms over the next two (2) days (Wednesday and Thursday) that may bring high-intensity rainfall causing ponding and increased runoff.
Beginning late this evening and into Wednesday morning, isolated thunderstorms are possible. The severity of possible thunderstorms is increased mid-day Wednesday through to the overnight. These thunderstorms may produce heavy rainfall, high winds, hail and/or a tornado. Rainfall up to 60mm is possible and at a rate of up to 50mm per hour. The risk of thunderstorms continues into Thursday, with scattered thunderstorms possible that could bring up to 25mm of rain and at a rate of up to 15mm per hour.
Thunderstorms bring the risk of high-intensity rainfall, and local peak hourly rainfall rates could be up to 50mm. 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.
If the upper ranges of the forecast are realized, total rainfall could be 90mm to 110mm between this evening and the end of Thursday.
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.
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. Please continue to monitor active weather alerts from Environment Canada.
This message will remain in effect until 12 p.m. on June 20th, 2025, unless otherwise updated.
