Western Canada is bracing for an unseasonable and extreme heat wave and dry spell that will raise the risk of wildfires in Alberta and British Columbia over the coming days.
University of British Columbia weather and wildfire researcher Chris Rodell says the hot, dry conditions will prime forest fuels for ignition, and he's concerned that lightning could spark fires after the heat wave eases.
Rodell says he expects instability in the atmosphere that could lead to thunderstorms and strengthen winds Tuesday or Wednesday.
The Alberta government declared a provincial state of emergency last weekend in response to fires that have forced thousands of people from their homes, and Rodell says the wildfire situation is also heating up in northeastern B.C.
He says temperatures in some areas look poised to exceed seasonal norms by about 10 degrees, a magnitude he described as extreme.
Environment Canada meteorologist John Cragg says the heat is coming from a "blocking pattern," when the normal fluctuation of low and high pressures stops, and warm air flows into an area without relief from an influx of cooler northern air.
While the heat is expected to peak on Sunday or Monday, Cragg says there's potential for the temperature-raising blocking pattern to return later next week.
The weather office is forecasting temperatures will hit 30 C and higher in parts of Alberta that are already grappling with early season wildfires.
Alberta's wildfire dashboard shows 76 active fires today, with most of the 23 fires classified as burning out of control clustered in the western half of the province.
Special air quality advisories have been issued in response to wildfire smoke for most of Alberta, as well as central and northeastern B.C.
The temperature is expected to hit 31 C in Edmonton on Monday, 30 C in Peace River and 29 C in Grand Prairie.
The heat is expected to settle in Friday and intensify over the weekend in B.C., where there were more than 40 wildfires on Wednesday.
B.C. Emergency Management Minister Bowinn Ma says officials are not currently anticipating a heat dome like the one that killed hundreds of people in 2021.
But she says the government will be closely monitoring conditions throughout the province, as elevated temperatures can still affect vulnerable people.
Ma says heat domes are a specific meteorological phenomenon characterized by persistent high pressure that caps heat over an area for a prolonged period.
A heat dome typically keeps temperatures high overnight, something that's not expected during the coming heat wave, she told media at the legislature.
Rodell says the coming heat wave doesn’t appear to share all the same atmospheric features that led to the heat dome and its record-breaking highs.
Environment Canada says the mercury will hit 28 C on Sunday and 30 C on Monday in Fort St. John, where a 29-square-kilometre wildfire is burning nearby.
The Peace River Regional District has issued an evacuation order for several dozen properties northwest of Fort St. John, while others are on alert.
There are two other wildfires of note burning in the province, meaning they're either highly visible or pose a potential threat to public safety.
The BC Wildfire Service has measured one of those fires at 59 square kilometres, spanning the boundary between B.C. and Alberta.
The other is an 11-square-kilometre blaze east of the Village of McBride, southeast of Prince George, where the temperature is expected to hit 33 C on Sunday.
The weather office says temperatures are expected to be a few degrees cooler closer to the coast, hitting 26 C in Vancouver that day and 28 C in Victoria.
This report by The Canadian Press was first published May 10, 2023.
The Canadian Press
