Alberta rescue officials are stepping up their avalanche warnings after two mountaineers were injured in a slide earlier this week near Canmore, west of Calgary. 

The two men were climbing Mount Charles Stewart on Tuesday when one was slightly injured after he triggered an avalanche. The other man suffered more serious injuries when he fell trying to assist his partner.

Public safety specialist Jeremy Mackenzie said the snow was softened up by warm weather and sun.

"It was a human-triggered avalanche, so it wasn't just the sun that triggered the avalanche, but certainly the heat and the radiation were contributing factors," he said. 

South-facing slopes

The avalanche risk in the area is still listed as considerable, but Mackenzie said warm weather can increase that risk during the daytime, especially on south-facing slopes.

"You can just expect that if it's going to be a sunny warm day, you're going to have a de-stabilization effect on the snow ... sometimes beginning as early as late in the morning, depending on where you're travelling and what's above you," said Mackenzie. 

"So it's just important to recognize that fact and avoid that terrain entirely or time your presence on that terrain."

He said it's best to avoid south-facing slopes in the afternoon, or even midday, depending on the circumstances.

Mackenzie also reminded those heading to the mountains to check avalanche conditions ahead of time and to always carry avalanche safety gear. 

With files from Dave Gilson