ABCA Flood Outlook/Water Safety - February 22, 2022

A warm front associated with a large low-pressure system will continue to bring unseasonably warm

temperatures throughout today and overnight tonight, reaching 10 degrees Celsius. The weather system will pull moisture from the Gulf of Mexico, producing a widespread rainfall event for southern Ontario. Based on the current forecast tracks, the heaviest rainfall will miss the ABCA watershed; however, general amounts of 10 millimetres can be expected. Light rain will begin this morning, becoming heavier in the afternoon, before clearing out overnight tonight, when temperatures fall back below freezing.

Current snowpack data shows approximately 15-30 mm of water equivalent in the snowpack. With a ripened snowpack, there is limited capacity to absorb appreciable rainfall. A quick snowmelt and runoff is expected.

Major flooding is not anticipated but, with levels in watercourses elevated from last week’s runoff, some rivers and creeks will reach and exceed bank-full conditions, resulting in minor flooding of traditional low-lying flood plain areas. Streamflows are forecasted to peak at levels lower than last week; however, additional rainfall amounts could produces similar levels to those observed last week. Flows in the smaller streams will peak overnight tonight, and the larger rivers through Thursday and Friday. Flows will remain high into the weekend.

Most of the larger rivers are running free of ice. The risk of ice-jam-related flooding is very low, as weakened river ice is only present in the Port Franks and Grand Bend areas. Municipal staff should monitor local drainage problem areas where snow conditions may have covered catch basins. Smaller rural watercourses have been drifted in by snow, which during a runoff, can block flows and back up water onto adjacent lands, resulting in localized flooding problems. Residents are reminded to stay away from all watercourses. The extremely cold water, combined with slippery and unstable stream banks, has created hazardous conditions near all waterways. Any remaining ice in ponded watercourses should be considered unsafe.

Contact: Davin Heinbuck, Water Resources Coordinator at 519-235-2610 or pager 519-931-0078

This message will remain in effect until 12:00 p.m. on Friday, February 25, 2022, unless local conditions

warrant further updates.