Environment Canada issued a severe thunderstorm warning for Calgary at about 6:30 a.m. MT. That alert was cancelled as of 9:40 a.m. MT.
However, warnings remain in effect for Strathmore, Brooks, Vulcan, Airdrie, Crossfield, Cochrane, Olds, Sundre, Drumheller, Three Hills and Rocky View County near Irricana and Beiseker.- Have images of the storm? Send photos or video to firstname.lastname@example.org
"Meteorologists are tracking a dangerous thunderstorm capable of producing up to penny size hail and flooding rain," the agency said on its website.
The storm caused flash-flooding in parts of northeast Calgary as well as Langdon and Chestermere east of the city.
The Alberta emergency public alert system tweeted a warning about overland flooding in Chestermere.
"Avoid driving through water on roads. Watch for possible washouts near rivers, creeks and culverts. Persons in low lying areas or valleys should watch for rapidly rising water and be prepared to move to higher ground," Environment Canada said.
"Lightning kills and injures Canadians every year. Remember, when thunder roars, go indoors," the weather agency added.
Crews extinguished a minor roof fire at a house in Coral Springs in northeast Calgary that was struck by lightning at about 7:30 a.m. MT, according to one fire official.
The utility company Enmax is reporting several localized power outages around the city caused by the thunderstorm.
Crews are working to restore power in sections of Forest Lawn, Dover, Erin Woods, Ogden and Valleyfield. The outages are affecting more than 7,000 customers, the company said.
The severe weather is also causing problems at the Calgary International Airport, where there have been several cancellations of early morning departures.