Experts foresee more unseasonal B.C. heat waves as May hot spell shatters records

The ongoing May heat wave that shattered almost 40 daily temperature records across B.C. and Alberta on Sunday should be seen as a warning of more out-of-season hot spells in the future, climatologists say.

The unseasonal hot weather, which has sent temperatures soaring 10 to 15 degrees higher than normal in some communities, broke more than 30 records in B.C., in towns including Cache Creek, Hope and Lillooet. The temperature peaked at 35.9 C in Lytton.

In Alberta, Sunday's temperature spike broke daily highs in places including Edmonton, Edson, Hinton and Jasper, all of which pushed close to 30 degrees for the day.

Joseph Shea, an associate professor in environmental geomatics at the University of Northern British Columbia, said Western Canada residents "need to adapt to a hotter future'' with more extended, out-of-season heat waves.

He said that includes the possibility of another "heat dome'' weather event this generation, referring to the excruciating 2021 phenomenon that killed hundreds of people in B.C. The odds of such an event occurring in any given year were once thought to be vanishingly small.

"I believe they attributed that heat dome event to be like a one-in-1,000-year event,'' Shea said. "... But climate change is proceeding right in front of our eyes, and those odds, I think, are changing. They're going to become more frequent.''

The current heat wave is not as severe as the 2021 heat dome event that set the all-time Canadian temperature record of 49.5 C in Lytton. But it has exacerbated both the wildfire and flooding situations in B.C. and Alberta, as snowpacks melt prematurely in large quantities while forests dry up and become susceptible to large blazes.

Shea said that as temperature spikes become longer and more frequent, wildfire seasons could also become longer and more expansive, impacting everything from forest ecosystems to water supply.

"If we get this [current] event in a month from now, we're gonna wind up in a very similar heat dome situation,'' he said.

A warning has also been issued for B.C.'s North Coast, including Kitimat and Terrace, with high temperatures in the forecast stretching into the long weekend.

The warning from Environment Canada says a plume of hot air is to remain in place over parts of B.C. through Thursday, bringing daytime highs to near 30 C and overnight lows near 15 C.

Andreanne Doyon, an assistant professor in the School of Resource and Environmental Management at Simon Fraser University, said the current temperature trends are very concerning, even if temperatures are not at heat-dome levels.

"We are not supposed to have heat like 10 to 15 degrees hotter than average in May,'' Doyon said. "... We know that things like heat waves are going to be more frequent, they are going to be more severe, and they're going to happen at times of the year where they previously haven't.''

Doyon said she was especially concerned about cities such as Vancouver, Calgary and Edmonton, where infrastructure such as pavement and concrete absorbs more heat than foliage and natural landscapes.