Potentially historic heat covers Western Canada,

Digital WritersThe Weather Network
Digital Writers

A prolonged 'heat-dome' event is yielding record-shattering temperatures to much of the West, most of it in B.C. with the worst of the heat. Residents are reminded to exercise caution and help prevent any human-caused wildfires from igniting. Here’s what you need to know.

Records continue to shatter across Alberta and B.C. as the provinces enter the third day of the intense heat wave, with the worst of it still to come.

Dozens of new daily temperature records have already been set in Western Canada, with several being all-time or monthly highs, since Friday (link)

British Columbia is where the heat is most extreme, with numerous communities opening cooling centres and initiating other measures to warn the public of the extreme temperatures. Power grids are likely to take significant hits and a lack of rain in the forecast means the fire danger is on the rise.

The dangerous heat is the result of what's colloquially referred to as a heat dome, something more common to the U.S. Southwest – an actual desert. It's an area of intense high pressure, beneath which descending air compresses into layers near the surface, warming drastically as it does so.

The result is a feedback loop: The warm air gets trapped in the lower elevations, and temperatures can only fall into the 20s at night. The following days can be incrementally toastier.

BC 1

The one upside for sun-lovers is that such features tend to be marked by clear skies, inhibiting the kind of vertical motion that produces clouds. It also keeps out low-pressure systems that can bring rain and thunderstorms. But the downside is that the dry conditions coincide with periods of drought conditions – and, as mentioned, elevated fire danger.

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Along with the daily temperature records being smashed, it's expected that many June temperature records, and even some all-time ones, are likely to fall once relief moves in.

BC Heat Recordsimage (3)

RELATED: Open burning to be banned across B.C. as heat wave hits

Below is a look at how the rest of this heat wave is expected to shake out.



Potentially the warmest days in history for some cities in B.C.

Record-maximum overnight lows, record daytime highs, record humidex values – it's all converging towards an extreme weather event. By the end of the weekend, the high-pressure ridge has surged so far north that some locations in the Northwest Territories have the chance to reach the upper 30s for daytime highs near the Alberta border.

Temperatures in the Interior can soar well into the low 40s for daytime highs. The warmest temperature recorded in June will probably fall – a whopping 42°C in Hedley during a 2015 heat wave in the province.


Alberta won't reach such extreme levels as British Columbia, but daytime highs in the mid-to-upper 30s will still be widespread – deeply uncomfortable even with such low humidity. This could also make way for some all-time temperature records to fall.

Back in B.C., a thermal trough – a thin, weak area of low pressure – tends to develop along the coast during these heat events, enhancing the offshore flow and allowing the air to further warm as it snakes down from the coastal mountains.

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“Climate change has altered our atmosphere, and I’m forecasting all-time temperatures on Vancouver Island - similar to levels seen in Dubai or Phoenix, Arizona,” says Tyler Hamilton, another meteorologist at The Weather Network. “It’s possible overnight lows will remain at 24°C or 25°C for some.”


Sunday morning and Monday morning will be warmer than the average daytime high for the end of June - bottoming out as high as 23°C, or even 24°C for some.

For some relief, head down to the Pacific Ocean, but it remains to be seen if the daytime sea-breeze will push very far inland, at all. Your best bet is to be directly in the ocean, or somehow find your way to Prince Rupert.


It's likely that the dangerous heat wave will continue into at least mid-week. The heat will also spread into Saskatchewan, with daytime temperatures pushing the mid-to-upper 30s by Tuesday.


The extreme heat should be taken seriously as it could harm your health and cause heat-related illnesses.

“Heat-related illness is the result of your body gaining heat faster than it can cool itself down,” states HealthLink BC on their website. “Those at increased risk for heat-related illness include: infants and children, people 65 years of age or older, and people who do a lot of physical activity or work in a hot environment. In most cases, heat-related illnesses are preventable.”

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Heat stroke is a life-threatening medical emergency. Call 9-1-1 or other emergency medical services as soon as you suspect or see the signs of heat stroke in an individual. Click here to learn more about heat stroke.

Heat stroke shares some symptoms with heat exhaustion, but the most acute to watch out for (according to Canadian Centre for Occupational Health and Safety) are:

  • Hot, dry skin or profuse sweating

  • Confusion

  • Loss of consciousness

  • Seizures

  • Very high body temperature

Heat stroke can follow on from untreated heat exhaustion, or can happen without little or no warning. To learn more about how extreme heat can impact the human body, click here.

Extreme heat safety tips


RELATED: Climate change boosted heat deaths by more than a third


The heat also ignites fears of human-caused wildfires. The B.C. Wildfire Service says nothing larger than a campfire will be allowed as of noon Friday across the province as scorching temperatures are expected to ramp up going into the weekend.

Residents are urged to exercise caution when outdoors. There are numerous ways human activity can start wildfires, some of which include open burning, the use of engines or vehicles, dropping burning substances such as cigarettes or the use of fireworks. The most important factor of person-caused fires is that they are preventable.

Residents are also reminded to check with local authorities before lighting a fire of any size.

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The City of Vancouver has implemented additional measures to protect residents facing compounded challenges of COVID-19 and the heat. Some of which include:

  • Community centres in the Downtown Eastside will offer water to patrons requesting it or in need of hydration, as well as supporting patrons with sun block. If you are out and about, you can fill up your water bottle at one of over 200 drinking fountains.

  • The City’s Non-Market Housing Operations is implementing a hot weather support plan for tenants, which includes increased wellness checks, and provision of bottled water and table-top fans for those residents not able or wanting to leave their rooms. Additionally, air-conditioned common area spaces will be available for residents to seek respite from the heat. Residents can find a list of the City’s 10 air-conditioned community centres and all library locations have air-conditioning at vancouver.ca/hot-weather.

  • Sharing heat safety messaging with operators of many of Vancouver’s SROs and requesting that they check on residents who are vulnerable to heat.

  • Emergency service personnel and volunteers will be vigilant for people who may be suffering from or are at risk of heat exposure.

The city will be providing additional information via Vancouver.ca to ensure people are aware of heat warnings and can access the information they need.

Be sure to check back as we continue to monitor this potentially life-threatening heat wave.

With files from Tyler Hamilton.