Issued at: March 16, 2023 at 11:50 a.m; Valid until: March 20, 2023

A strong low-pressure system is forecast to enter the province today and slowly track across the region. The system will bring warmer air and precipitation. Air temperatures in south western Ontario are expected to remain above freezing until early Saturday, possibly reaching 8 C on Friday.

Total precipitation accumulation amounts for the duration of this storm are forecast between 20 – 25 mm in the region, beginning late Thursday and continuing into Friday afternoon. A watershed wide snow survey conducted Wednesday measured an average of 70 mm of water equivalent, ranging from 100 mm north of Stratford, to 75 mm in London and Woodstock.

The Upper Thames River Conservation Authority (UTRCA) expects water levels in streams and rivers will respond to the forecast rain and warm temperatures. If temperature and precipitation forecasts materialize, runoff totals and corresponding water levels are expected to be similar in magnitude to events experienced earlier this year, with some traditional low-lying flood plain areas being inundated. The UTRCA expects water levels to be elevated starting on Friday, and remaining high over the weekend. Serious flooding is not anticipated at this time. The snow pack will likely be reduced, but will not disappear.

The UTRCA’s flood control reservoirs at Fanshawe, Wildwood, and Pittock Conservation Areas are at seasonal levels and will be operated to reduce downstream flooding. UTRCA officials are monitoring the situation and will report any changing conditions.

Residents are reminded to use extreme caution near all watercourses and caregivers are reminded to keep children and pets away from watercourses. Stream banks can be slippery and unstable and the water is extremely cold, fast-moving, and higher than normal. Any ice cover will be weakened and unstable. Flood control reservoirs are especially hazardous due to fluctuating water levels.

As water levels rise, it is not safe to take shelter along riverbanks or in low lying areas that are prone to flooding.

• See Thames River water levels and flows
• Types of flood bulletins
• Find out how the UTRCA manages floods