A heat warning was issued Friday afternoon for Calgary and Rocky View County, as a “prolonged, dangerous and potentially historic” heat wave is making its way across the province.
“Afternoon high temperatures near 30 degrees Celsius on Friday will climb to the mid 30s by Sunday, and could approach 40 C in some regions early next week,” Environment and Climate Change Canada said in the advisory.
“Little to no reprieve from the heat is expected, as overnight lows will remain between 15 and 20 C.”
The weather agency said the “duration and magnitude” of the heat wave means there’s an increased risk of heat-related illness and people are warned to take precautions to protect themselves and others.
A stretch of extreme heat is heading towards B.C. and Alberta and meteorologists aren’t exactly sure when it will end.
“We have a large ridge of warm air aloft moving in from the United States, so it’s coming up from the south,” said Sara Hoffman, a meteorologist with Environment and Climate Change Canada.
“It’s over B.C. and Alberta. It’s going to persist for some time… We’re expecting it to go at least a week and we actually don’t know the full end when we’ll cool below extreme heat temperatures,” she explained.
“The long duration — coupled with little reprieve from the heat overnight — will create a very dangerous situation.”
The people most at risk during an extreme heat event are older adults, those experiencing homelessness and anyone with pre-existing health conditions.
“If you have an older relative living alone, it’ll be important to make sure that they’re staying cool, drinking enough water, that type of thing,” Hoffman said.
Heat exhaustion and heat stroke can set in quickly so avoid strenuous activities in peak heat hours and stay hydrated and out of the sun if possible.
Hoffman said animal safety will also be important.
“If it’s too hot for you, it’s too hot for your pet.”
The duration of this extreme heat event, combined with the oppressive temperatures, make it very uncommon in Alberta, Hoffman said.
“This is a very rare and important heat wave and it’s important for everyone to treat it as such.
“With this event, we’re forecasting daytime highs well over 30 C… The last time we had four days of 32 C as a daytime high in a row was 1961,” she added.
“This will be a historical heat wave.”
Global Calgary meteorologist Tiffany Lizée said the heat wave is expected to last until at least July 2.
B.C. will see the highest temperatures from this event, Hoffman said, before the heat moves into Alberta through Slave Lake, Edmonton and then south to Red Deer and Calgary.
“The hardest hit will be northwestern Alberta,” she said.
The all-time record for hottest temperature in Edmonton is 37.2 C, which was hit on June 29, 1937.
The all-time record for hottest temperature in Calgary is 36.5 C, which was hit Aug. 10, 2018.
“We are forecasting daytime highs in the mid 30s — so the 35 to 36 C range — we’re anticipating it to get that hot,” Hoffman said.
Edmonton averages four days per year above 30 C.
Calgary usually has five days per year above 30 C.
“We could be looking at a stretch of seven days or more with highs in the 30 to 35 C range in Edmonton,” said Global Edmonton’s chief meteorologist Jesse Beyer.
The last time Edmonton had five days in a row of temperatures above 32 C was June 2-6, 1961.
The last time Calgary had five days in a row of temperatures above 32 C was July 30 to Aug. 3, 1914 — more than a century ago.
“The placement and pattern of the jet stream will lead to the heat wave and dictate its intensity.
“Not only will the high be in the minimum 30s, but the overnight lows could stay as warm as 20C,” Beyer said. “This doesn’t allow the body to cool and can lead to significant stress for many.”
The hottest temperature ever recorded in Alberta was on July 21, 1931 when Bassano hit 43.3 C.
The hottest temperature ever recorded in Canada was on July 5, 1937. Both Yellow Grass, Sask., and Midale, Sask., hit 45.0 C.
In terms of long-term weather trends, Hoffman said the weather agency can’t attribute any one heat wave or any one extreme weather event to climate change.
“But what we can say with pretty good certainty is that with the changing climate, we expect more frequency and severity of heat-related events like this in the future.”
— With files from Morgan Black, Global News