A severe thunderstorm with golf ball-sized hail could arrive in Calgary between Sunday afternoon and early evening, according to Environment Canada, causing unusually significant damage.
The weather agency issued an orange-tiered thunderstorm watch, meaning the storm isn’t imminent but likely, said Todd Bate, lead meteorologist with Environment and Climate Change Canada. Warnings are generally issued half an hour before the weather event.
“The watch in effect is because yesterday we’ve observed a number of large damaging hailstorms over central Alberta, and we’ve seen that the weather regime move southwards into southern Alberta,” Bate said.
“And we’re concerned particularly about hail for this region.”
The damage from the hail, at its worst, could be comparable to the storm in 2024, which inflicted upwards of $3 billion in insurance claims while destroying parts of the roof of Calgary’s International Airport.
Bate ascribed the conditions to a pocket of cold, turbulent air high up in the atmosphere that is rolling into the region, creating an environment that is highly unstable. Higher temperatures further destabilize those conditions by pushing hot air higher toward the cold winds.
“We did anticipate the potential for severe weather yesterday in some areas of Red Deer. It was a little bit more intense, perhaps, than we anticipated with our watch, so that’s why we have a higher level watch for today,” Bate said.
He advised Calgarians to monitor weather alerts and heed the agency’s advice.
“If you hear lightning is getting nearby, that’s when we’d ask you to go indoors,” Bate said. “In fact, we have a saying, when thunder roars, go indoors.”
Rain didn’t damper Day 3 of the Calgary Stampede Rodeo in Calgary on Sunday, July 5, 2026.
Stampede prepared for weather
Kerrie Blizzard, director of public safety and environment at Calgary Stampede, said the organizing teams of different events are receiving weather updates by the minute. For example, the risk of damage for a larger ride is higher than other outdoor events. As a result, different events with various levels of risk have their weather tracking systems.
Blizzard also said the festival has mass notification systems that will send out notifications to all organizers and the public. The festival has contingency plans in place, including cancelling outdoor shows ahead of a severe storm, but has the capacity to restore the event once the weather clears.
“The great thing about Calgary weather is that it changes fairly rapidly,” Blizzard said, encouraging visitors to try out the festival’s indoor programming.
“We have a ton of indoor opportunities for our guests to enjoy some great entertainment while we have inclement weather.”
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