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You can credit last week’s atmospheric river. It brought a large volume of snow at upper elevations and rain at lower elevations, creating high to extreme avalanches hazard in the parks. “So getting a big result wasn’t unexpected (but) getting a result that big was unexpected.”
That’s how Conrad Janzen, a visitor safety specialist with Parks Canada, describes his reaction to watching an huge avalanche cover the Icefields Parkway during avalanche control work on Highway 93, north of Lake Louise on Saturday morning.
“The avalanche itself was close to 500 metres wide and traveled a total distance of about two and a half kilometres downhill to reach the highway — and then ended up putting a pile of debris on the highway that’s about 250 metres long and six to eight metres high,” Jansen said. “That’s the equivalent of kind of two football fields and a bit — and then the height of about a two-story building and really dense, hard, almost ice-like snow.”
The avalanche, near Mount Hector, about 20 minutes north of Lake Louise, was triggered by two charges of explosives dropped from a helicopter by Parks Canada avalanche control experts.
From the air, the true scale of the avalanche is evident, with vehicles appearing tiny against the massive pile of snow.
The atmospheric river of rain that soaked much of British Columbia last week, and resulted in heavy snowfall at higher elevations, created an extreme avalanche danger in much of southern B.C. and Alberta.
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While cooler temperatures since then have mitigated some of the danger, Janzen said similar-sized avalanches were also recorded in the backcountry areas of the national parks, a dramatic demonstration of just how dangerous the avalanche conditions were.
Luckily, there were no reports of anyone getting caught in the avalanches.
“We’re rating it as considerable still in the Alpine, which means human triggering is still likely in certain spots, and moderate at tree line and low below tree line,” Janzen said.
“We will see another storm arriving Tuesday night and Wednesday, and we could get up to 40 centimetres of new snow in the Alpine with that storm. So, we’ll probably see another bump in the avalanche hazard, possibly even reaching high danger levels in the Alpine for Wednesday and Thursday.”
Despite the decrease in the avalanche hazard over the past couple days, the Icefields Parkway (Highway 93) remains closed while crews work to clear the snow and debris.
Because there is so much hard packed snow, as well as lots of trees and other debris, Janzen expects the highway to be closed until at least Saturday, Mar. 28, and maybe longer.
“It is the largest amount of debris that we’ve had on one of the highways in a long period of time,” Janzen said.
He recommends anyone planning to use Highway 93 check 511 Alberta for up-to-date information on when the highway could reopen and have a back-up travel plan in place in case the closure lasts longer than expected.
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