'Ferocious' spring avalanches should elicit caution from backcountry travellers, say experts

Avalanche experts are reminding backcountry travellers to stay alert despite the warmer weather, as sunny skies can be one of the triggers that sets off an unstable snowpack.

"It warms up every spring so it's kind of a given. The difference is what's warming up," said Canmore avalanche protection consultant Chris Stethem.

Stethem said there were a number of avalanches this winter, and once it starts warming up it can easily trigger unstable layers of accumulated, packed snow.

He said there are three big factors at play: sun, temperature and precipitation.

"Those spring avalanches can be fairly ferocious, sizeable events," he said.

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Stethem said a so-called "alpine start" — heading out early in the day while temperatures are still cool can be one way to stay safe.

But it's not foolproof.

"If you get out to the mountains on a Saturday morning and it's been warm all night, Friday night, then you'd better make it a pretty modest objective," he said.

That was a message James Floyer with Avalanche Canada echoed.

"I would say that if you're going into an area where there has been a significant amount of recent snow then maybe it's a time to still be really cautious of those steep slopes, regardless of the time of day that you're traveling," he said.

Floyer said the central Rocky Mountains, including Banff, Yoho and Kootenay, saw increased snowfall in recent days and that conditions can vary significantly across short distances at this time of year. 

He recommended users avoid steep terrain after snow storms, keep an eye on features like cornices and snow slabs, and carry avalanche safety gear.

The main thing, he said, it to be both mindful and adaptable.

"All of this boils down to a question of risk. You may be or may see yourself as a risk-taker … we have to think a little bit about our risk tolerance and our knowledge of risk," said Stethem.

Avalanche Canada plans to issue its last avalanche forecast for the season later this week.