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Most of B.C. now under a 'dangerous' heat warning — here's why

Covering up with a hat to ward off heat exhaustion is a must, says Environment Canada.

A heat wave consuming huge swaths of North America is set to hit British Columbia, bringing unprecedented temperatures and triggering extreme weather warnings across Western Canada. 

On Wednesday, the Meteorological Service of Canada forecasted unprecedented temperatures over the next several days, warning of daytime highs above 40 C across some areas of B.C.

By late afternoon, Environment Canada had issued 31 public weather alerts due to "a dangerous long-duration heat wave," set to hit the region Friday and stay until Tuesday. The warnings cover an area stretching from the northeast corner of B.C. to the east coast of Vancouver Island, and encompass Metro Vancouver and much of the province’s Interior. 

Humidity will make temperatures in Metro Vancouver feel as high as 43 C Sunday and Monday, according to The Weather Network. In Kamloops, temperatures are expected to feel like 44 C Sunday, and in Abbotsford, highs could feel like 48 C Monday.

The extreme weather warnings come amid growing drought-like conditions across much of southern British Columbia.

Armel Castellan, a warning preparedness meteorologist with Environment Canada, describes the incoming weather as “the main event” after a dry May. 

“It’s been so dry. We’ve had record-breaking dryness for the Interior and south coast,” says Castellan. “Now, we’re talking about dangerous conditions.”

“It might even be looking at all-time records for some locations.”


If records were to fall in June, it would buck annual trends where the hottest days come in July and August, Castellan explains.

The weather is expected to be so hot, it is being treated as a public health threat, with infants and young children, older adults and people with chronic conditions facing the greatest risks. Those working outside in such conditions also need to protect themselves as best they can. 

Environment Canada recommends drinking plenty of water, checking in on older family, friends and neighbours, and to check for signs of heat illness, such as:

  • dizziness/fainting; 
  • nausea/vomiting; 
  • rapid breathing and heartbeat; 
  • extreme thirst; 
  • decreased urination with unusually dark urine.

More information can be found on the HealthLink BC website or by calling 811. 

In Kamloops, where Environment Canada forecasts temperatures to hit 40 C Saturday through Monday, a local homelessness outreach group warned the rising heat would lead to “fatal consequences.”

“URGENT!“ writes The Mustard Seed in a call for donations from its supporters Wednesday, after going through a few hundred cases of water within the last week.

“With temperatures reaching close to 40 degrees over the next week, those individuals out all day on the street are about to face another heat wave... We have run out of water bottles to support those living on the street.”

Castellan echoes the call to protect B.C.’s most vulnerable from heatstroke and death. 

“Yes, we might see wildfires start; yes, we might see drought get worse and worse, but in the immediate term, there’s lots we can do to prepare for this heat,” says Castellan.

The coming heat is expected to be made worse by extreme UV indexes. So soon after the solstice, UV levels have reached peak levels in many parts of the province; covering up with a hat to ward off heat exhaustion is a must, he says.

Castellan also recommends anyone with an air conditioner check that it’s in working order. Those without one should check in with their local municipality to see what buildings will be offered up as cooling stations.

The evening is not expected to offer much respite. 

“We’re talking about maybe 20 degrees overnight,” says Castellan. “Our bodies won’t have the opportunity to cool off and recharge for the next day of heat.” 


Drought conditions have been building across much of the North American west for months now. But the latest heat wave is something else. 

Faron Anslow leads climate analysis and monitoring at the Victoria-based Pacific Climate Impact Consortium. He says it’s normal for the heat dome usually sitting on top of the U.S. southwest to push into B.C. over the summer. 

A heat dome forms when the jet stream migrates north, allowing an intense, high-pressure system to create a cap over hot ocean air. When that air descends, it warms. By trapping heat at the surface, the "dome" creates a feedback effect leading to sweltering conditions from day to night. 

What’s different about the approaching high-pressure ridge this time is its “huge amplitude.”

“This is in that more rare category,” says Anslow. “The ridge from north to south is large. It’s got a lot of hot air embedded in it.”

That wave of high pressure is so large, says Anslow, that it’s expected to bring extreme hot weather to a region stretching from Oregon to southern Alaska. It’s also expected to bounce back with another round of hot weather a week later. 

“We’re looking at what might be a pretty long event,” he tells Glacier Media. 

The climatologist says when he looks back at the climate record in B.C., the upcoming five-day average is on the order of 8 to 10 degrees Celsius above normal. 

Climate scientists are not quite at the point where they can pin a single extreme weather event to climate change on the fly, but all the telltale signs are there, says Anslow.

“What we can say is that these heat waves are consistent with climate change. They line up with what we expect from climate models,” he says.

A European heat wave that consumed the continent and shattered temperature records in 2019 was found to have been five times more likely to occur because of climate change.

Anslow says he wouldn’t be surprised if data revealed a similar connection for B.C.’s upcoming heat wave.

And with snowpack already at below-average levels in watersheds around Vancouver, the Middle Fraser and South Thompson regions, the forecast points to more drought and a higher risk of wildfire (this week, the BC Wildfire Service logged 16 new fires, raising the rolling yearly total to 227).

Stefan Labbé is a solutions journalist. That means he covers how people are responding to problems linked to climate change — from housing to energy and everything in between. Have a story idea? Get in touch. Email [email protected].