Southern Manitoba soaking expected to last until Saturday afternoon

Posted on May 24, 2024 by Peggy

The drenching rain has started in southern Manitoba. And in some areas — gulp — there’s snow.

A strong low-pressure system has tracked in from the Dakotas and is expected to linger until midday Saturday, soaking the region with 50-60 millimetres of precipitation and potentially causing flooding in low-lying areas, Environment Canada says.

The weather agency first issued a rainfall warning on Thursday about the approaching system. At that time, it was primarily expected to impact the Red River Valley, a small part of the Interlake and everything through the Whiteshell.

The warning area has since expanded to include much more of the Interlake and southern Manitoba.

It has also brought strong north winds, with gusts between 40-60 km/h, and much cooler temperatures.

Rain mixed with snow is expected in Brandon, while some areas closer to the international border already had a thin layer of white on their spring lawns on Friday morning.

A high of only 8 C is forecast for most areas in the south on Friday, and Winnipeg won’t get much warmer than that on Saturday, either, Environment Canada said.

Snow is seen covering a lawn and deck while trees have fresh spring leaves. — Snow in May! Deb Bauche sent in this photo from Friday morning in the Turtle Mountain area, just north of the International Peace Gardens in southwestern Manitoba. (Submitted by Deb Bauche)

The normal high for this time of year is 21 C.

The expected extent of the deluge has prompted the province to issue an overland flood warning for some areas.

“Heavy precipitation in short duration could create high surface runoff and overland flooding,” the bulletin says.

Manitoba Transportation and Infrastructure’s Hydrologic Forecast Centre says up to 80 mm of precipitation has already fallen in the past three days in the Winnipeg River system and in the Lake of the Woods watershed.

The department is opening control gates along the Whiteshell lakes to balance and manage the expected level rises along the lakes.

A map of southern Manitoba with areas highlighted in red. — The areas in red are under the Environment Canada rainfall warning. (Environment Canada)

The high winds could also raise water levels by as much as five feet or more along the south basin of Lake Manitoba, as well as shorelines near Gimli on the west side and Victoria Beach on the east side of Lake Winnipeg, the bulletin says.

Property owners are advised to take precautions.

Heavy rain can cause water to back up into basements and sewage to be released into the rivers, as happened last week when hail-packed thunderstorms brought powerful winds and tornado warnings to south-central Manitoba.

Winnipeg was hit hardest by that system, though rain amounts varied greatly, from 10-12 mm in the east and southeast areas of the city to 29-35 mm in the west and central areas.

More than 20 megalitres of sewage was released into the Red River during that time.

About a third of the city relies on a combined sewer system — pipes that collect both raw sewage and runoff from rainfall or melting snow. The combined water is sent to a sewage treatment plants, but in periods of very heavy rain, it goes directly into the rivers in order to avoid backup into basements.

But that doesn’t always work, either.

More than a dozen people on Truro Street in the St. James neighbourhood had water and sewage back up into their basements last week. And they’re worried about it happening again.

“Your heart completely stops, your stomach drops and you’re thinking, is that what I think it is?” Jennifer Schappert said about realizing her basement was flooding last week.

She and 17 of her neighbours have joined a Facebook group called Truro Street Basement Flooding “to chat, rant, compare notes” and generally support one another.

On Friday, at least one person was reporting flooding once again.

In a statement, the city said it is aware of the issues on Truro and is working to fix them. It also offers tips on how all city residents can reduce the risk of basement flooding.