Warm Temperatures and 20-25 Millimetres of Rain Could Present the Risk of Minor Flooding

by Bob Montgomery

Ausable Bayfield Water Resources Supervisor Davin Heinbuck says periods of rain in advance of an approaching low-pressure system could bring rainfall totals of 25 millimetres to the Ausable Bayfield watershed area over the next 36 hours. The first wave of light rain is expected Wednesday afternoon, followed by a period of dry weather before the heavier rains begin tomorrow evening. Heavy rains are expected overnight Thursday, before drier weather settles in for the weekend.

The forecasted rain, and temperatures remaining above freezing over the next several days, will melt most of the snowpack. Snow survey data from today shows that the water equivalent in the snowpack ranges between 25-35 mm. With a combination of rainfall and snow melt on saturated soils, a quick runoff is expected.

Based on the current rainfall predictions, river-flow forecast models indicate that levels in watercourses will rise quickly Thursday evening, peaking in the northern portions of the watershed by Friday. While many watercourses are expected to exceed their banks, major flooding is not anticipated at this time, with flooded areas limited to the low-lying undeveloped flood plains. The potential extent of flooding will depend on the actual temperatures and rainfall.

Residents are reminded that all ice should be considered unsafe.