The tornado warning near Okotoks has ended, but there were reports a tornado touched down near the southern Alberta town this evening.
Chris Wielki of Environment Canada said they saw rotation on the radar near De Winton, Alta., which is located between Calgary and Okotoks.
"There was a thunderstorm that developed over southeastern Calgary that tracked to the south about 20 to 25 km/h," he said.
He said a pilot reported seeing a tornado touch down for about 15 minutes near the De Winton Highwood Airport. There have been no reports of damage so far.
CBC meteorologist Johanna Wagstaffe said Environment Canada has to have visual confirmation to confirm the rotation that can be seen on radar is a tornado, so either a photo or a reputable source like a storm chaser or pilot.
She said Environment Canada also sends out a damage survey team to look for indications that a tornado hit the area.
Officials are advising residents to take cover if threatening weather approaches.
"Get low and put as many walls between yourself and the storm as possible," said an Alberta Emergency Alert.
"Stay away from windows, doors and outside walls. If you are on the highway and cannot avoid the tornado, seek shelter in a ditch or ravine."
The bulk of southern Alberta is now under a severe thunderstorm watch after several dangerous storms rolled through the province earlier this evening.
Heavy rain and hail hit southeast Calgary and residents of Pincher Creek also saw large pieces of hail fall from the sky.Wielki said tornado warnings are not as common as thunderstorm warnings in Alberta.