Flood risk rises as Colorado low bears down on Manitoba

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This article was published 21/04/2022 (1364 days ago), so information in it may no longer be current.

Expect a wet weekend — and potential flooding.

Environment Canada has forecast heavy snow, rain and strong winds across most of southern and central Manitoba as another Colorado low is about to move through the province beginning Friday and lasting until Monday.

“It’s going to be a very interesting system, sweeping up out of Colorado — a classic late winter/ early spring storm,” Environment Canada meteorologist Brian Proctor said.

“It is going to be a very messy weekend,” he said.

Provincial flood forecasters followed up by issuing an overland flood warning for a significant swath of southern Manitoba. The hydrologic forecast centre expects a huge amount of precipitation that could overwhelm rivers and streams and flood low-lying properties and roads.

The area under the weather warning is from the Saskatchewan border to Highway 12 east of Winnipeg, and from the United States border to the Trans-Canada Highway. The flooding could even extend north of the Trans-Canada, depending on snowfall and rain amounts.

More than 50 millimetres of rain and snow could fall in the areas under the flood warning, while some locations could receive as much as 80 mm by Monday.

Winnipeg, the Red River Valley and the southeast will have a mainly cold, rainy and windy weekend, with some snow and possibly freezing rain.

The system is expected to begin in Winnipeg at around 3 a.m. to 4 a.m. Friday — a band of snow that will shift to about five to 10 millimetres of rain in the morning, Proctor said. Temperatures will likely hover just above the freezing point.

Wind speeds will increase Saturday night, and the rain will likely turn to snow through Sunday, Proctor said.

As of mid-day Thursday, Winnipeg is forecast to get about 20 to 40 mm of rain from Friday to late Saturday, with about five centimetres of snow Sunday.

“The majority of the heaviest rain is likely to fall Saturday afternoon to Saturday evening,” Proctor said.

There is a potential for freezing rain along the U.S. border early in the day, the weather agency said in its alert. The system is expected to move into Ontario on Monday, but light, lingering flurries will remain for most of the province.

The weather agency forecasts a swath of “very heavy snow” will move from southeastern Saskatchewan through the Manitoba Parklands and the Interlake with total accumulations of 25 to 50 cm of wet snow, while “very strong winds” will blow snow at times, hampering visibility. There will likely be areas of freezing rain, too, Environment Canada said.

“They’ll probably see the heaviest amount there,” Proctor said.

The weather agency hedged the potential of the system in its weather alert, noting Colorado lows are “notoriously difficult to predict,” meaning forecast details and potential impacts will change over the weekend.

The significant amount of new precipitation has the potential to increase the spring flood risk to moderate-to-major levels in the Red River Valley.

If the forecast is accurate, April will be the second-wettest month in the Red River Valley since 1950, only surpassed by April 1986, the executive director of the province’s hydrologic forecasting centre, Fisaha Unduche, said Wednesday.

erik.pindera@freepress.mb.ca

Twitter: @erik_pindera