Warm weather increases avalanche danger

Conditions ripe for natural and human-triggered avalances: Avalanche Canada

With record warm temperatures across the southern Interior come increased avalanche danger, according to the Avalanche Canada.

In Cranbrook, temperatures reached a high of 10 degrees C on Monday, after reaching a high of 6 degrees C on Sunday.

That kind of weather pattern has resulted in a danger rating of considerable in the Purcells and in the alpine region of the South Rockies, according to Avalanche Canada’s rating system.

“Avalanche hazard is going to remain considerable in the alpine and the treeline through till Thursday when the temperatures cool,” said Eirik Sharp, a public avalanche forecaster, “and that’s just a result of the warm temperatures continuing to stress that snow and not letting it heal.”

According to Avalanche Canada’s bulletin on the Purcell region, a weak layer of surface hoar above a crust is buried by 40-70 centimetres of snow. That layer remains touchy and has the potential to be triggered naturally or by humans. In the South Rockies, the bulletin says a surface avalanche or cornice fall could step down to a deeper layer that would create a very large avalanche.

“We’ve had a pretty significant load in the form of recent snow and rain to the snowpack in the Purcells and the South Rockies,” continued Sharp. “Whereas avalanche activity would typically subside and slow down in the wake of the storm, what we’re seeing is these warm temperatures are causing a prolonged cycle.

“So we expect to see avalanche activity, both natural and human-triggered avalanche activity likely until temperatures cool on Thursday.”

Temperatures will remain in the low single digits throughout the rest of the week, but the current warm spell will have implications for the rest of the avalanche season.

“Depending on how quickly and what happens after temperatures cool with the next weather coming in, could drastically change the future course of the season,” said Sharp. “It’s a period of uncertainty now, as to how the rest of the season shapes up.”