Manitoba waits for rain amid extreme drought, heat

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This article was published 09/07/2021 (1168 days ago), so information in it may no longer be current.

Dry weather is parching southern Manitoba, and continued heat is feeding into a “vicious cycle.”

“For how long it’s been as dry as it’s been in southern and southwestern Manitoba, I’ve at no point in my career seen anything like that before,” said Environment Canada meteorologist Sara Hoffman.

It’s been a month since Winnipeg has gotten a rain of any significance, and rains before that have been few and far between, she said.

The Canadian Drought Monitor has declared “exceptional drought” in many parts of the province.

“And that is as high as the ratings go,” said Hoffman.

Exacerbating the problem is continued heat. A massive heat wave swept over much of the country in recent weeks and temperatures are again on the rise, said Hoffman.

“As a meteorologist and a scientist, yes, I find it concerning,” she said. “Extreme events like extreme drought, flooding, forest fires, extreme heat events like we just experienced here in Western Canada — with climate change, we only expect those to increase in intensity and frequency for the future.”

Hoffman said the “heat dome” systems hovering over Manitoba quash potential precipitation. Thunderstorms are the main driver for precipitation on the Prairies, she said, and the stagnant or descending air of these hot weather systems prevent the turbulence of hot air colliding with cool air, which helps create those storms.

That heat and dryness leads to more heat and dryness, said Hoffman. Pools of water or moisture in soil evaporates and drifts off while the “heat dome” prevents storms. In wetter years, another source of water for precipitation comes from plants and crops, through a process called evapotranspiration.

“On the Prairies we often joke as meteorologists that we can know when an area has harvested its crop, because we see that the moisture source, later on in the day, is just cut,” she said. “Definitely evapotranspiration from plants is a huge factor.”

The lack of precipitation has led to the Rural Municipality of St. Laurent to declare an agricultural state of disaster Monday. With rainfall scarce throughout southern Manitoba and the Interlake, it’s expected other rural municipalities will follow suit.

“It’s a vicious cycle — if you’re not getting a lot of water to start, you’re not having a healthy crop to start off with, and then you’re not getting that evapotranspiration from the crop to help generate a thunderstorm or precipitation,” said Hoffman.

As of Saturday evening, there was a 60 per cent chance of rain forecast for Monday. All other days in the seven-day forecast are dry and hovering near or over 30 C.

 

cody.sellar@freepress.mb.ca