Western Canada melts as weather swings from extreme cold to record highs, rain

Some Western Canadians are swapping their parkas for T-shirts and raincoats after swinging from record high temperatures to record lows and back again this winter.

“It’s been a bit of a weather whiplash scenario,” said Armel Castellan, a meteorologist with Environment and Climate Change Canada (ECCC).

In B.C., West Vancouver and Abbotsford set all-time January temperature records Tuesday amid an atmospheric river event, hitting 18.2 and 17.3 C, respectively. More than 30 spots across B.C. broke daily records, according to ECCC.

But it’s not all sunshine. The southwestern portion of the province is facing heavy rain, with ECCC warning of flooding, pooling water and landslides through midweek for Vancouver Island, the Sunshine Coast, Vancouver and Howe Sound.

B.C.’s River Forecast Centre expanded a flood warning to include the Lillooet River, and by Tuesday afternoon, the Village of Pemberton had declared a local state of emergency and issued an evacuation order for several properties.

The next wave of precipitation is expected Wednesday morning, Castellan said.

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From mild December to deep freeze to thaw

Temperatures were well above normal at the start of the week for much of southern B.C., Alberta, northern Saskatchewan and northwestern Manitoba, as well as parts of southern Yukon and the Northwest Territories.

Calgary and Edmonton hit daily record highs on Tuesday, 15.1 C and 12 C respectively, with Edmonton recording its highest January temperature since 1941.

It’s a far cry from two weeks ago, when Western Canada was under extreme cold warnings, with some areas falling below -40 C and several cities breaking daily low temperature records as a polar vortex swept through the area, leading to flight and school bus cancellations.

Alberta’s biggest temperature jump was recorded just north of High Level. According to Alysa Pederson, a warning preparedness meteorologist with ECCC, a weather station in Keg River hit 14.4 C Monday, after a low of -50.6 C two weeks ago — marking a change of 65 C.

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Before the mid-month cold snap, much of Western Canada saw the warmest December on record.

“We went from warm, above seasonal, to way below seasonal for the better part of a week, and then right back up to above seasonal,” Castellan said.

Meanwhile, parts of northern Canada are experiencing the opposite swing. Iqaluit reached a daily record high of 3.3 C on Jan. 15 when the south was in a deep freeze, but the Nunavut capital is now under an extreme cold warning, with a forecast high of -32 C Wednesday.

When Alberta was cold in the middle of the month, Baffin Island was warmer than places in southwestern Canada, said Castellan.

“And then we switch back into this other pattern, and now northern Quebec and Labrador and parts of Baffin Island are on the colder side.”

Wild weather swings impact infrastructure

Temperatures are expected to slide back toward normal on the weekend, with highs in the single-digits below zero predicted for Edmonton and Calgary by next week.

For Canadians enjoying the thaw, Castellan urged people to be careful in the coming days as pooling water can refreeze on surfaces like sidewalks and roads, making driving and walking surfaces slippery.

Altaf Arain, professor in the School of Earth, Environment and Society at McMaster University in Hamilton and founding director of the McMaster Centre for Climate Change, said the rapid and frequent freeze-thaw cycles are also doing a number on infrastructure.

The impact is more immediate in northern communities that rely on frozen roads for transportation. In Canada’s southern cities and towns, concerns centre more around roads and building foundations, Arain said.

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For example, water that seeps into a crack when temperatures are above zero will expand in volume by 10 per cent when it freezes, he said, making the crack bigger. The more that process repeats, the more problems it can cause.

“It you’re freezing and thawing every other night, like what we are seeing — in the daytime it’s plus five, at nighttime it’s [below] zero — it’s more frequent,” Arain said. “It may not appear right away, but the cracks are now bigger.”

Arain said he expects to see more weather ups and downs through February.

While much of this year’s unseasonable warmth has been attributed to El Niño, climate change increases the extremity and back-and-forth fluctuation of weather systems, making the impacts of these weather systems more severe, as evidenced by 2023 being the planet’s hottest year on record.

“If there will be precipitation, it will be larger because the warmer air will hold more water. So then extremes become more extreme,” Arain said. “Most years are extreme now.”