"A persistent weak layer within the snowpack" has prompted Avalanche Canada, in conjunction with Parks Canada and Alberta's Kananaskis Country, to issue a Special Public Avalanche Warning for recreational users of backcountry and front-country avalanche terrain throughout Southern B.C. and Western Alberta, including the Sea to Sky corridor.
While Whistlerites were singing the praises of a recent storm that dumped tens of centimetres of eagerly-awaited snow across the resort—and the rest of Western Canada—that snow is now sitting "precariously" on the aforementioned weak layer.
"Although the nature of the layer differs across the ranges, the effect is the same," Avalanche Canada explained in a release. According to the organization, many avalanches on that weak layer ran to historic runouts during the storm.
"The danger ratings are going down across the map because naturally running avalanches have slowed down or stopped," explained Ilya Storm, forecast program supervisor for Avalanche Canada, in the release.
"However, now many slopes are primed for human-triggered avalanches. Distinguishing between slopes that have already slid and those that are the tipping point will be very difficult. This, combined with clearing weather during a holiday week, has us very concerned for backcountry users."
Avalanche Canada, Parks Canada, and Kananaskis Country warns all backcountry users recreating in avalanche terrain-including those ducking ski area boundary ropes-to always check their regional avalanche forecasts at www.avalanche.ca.
Everyone in each backcountry party needs the essential rescue gear-transceiver, probe and shovel-and know how to use it. Avalanche Canada is reminding backcountry users to ensure their party re-groups "well away from avalanche slopes, including overhead hazard such as cornices."
The warning also reminds those heading to the mountains to snowshoe or explore popular summer trails that many of those "front country" areas are exposed to avalanche terrain. Avalanche Canada recommends planning ahead, researching your route to make sure you are avoiding these areas, or hiring a certified guide to lead your party.
The warning, in effect immediately, applies to the following forecast regions:
Sea to Sky
South Coast Inland
Purcells
South Rockies
Kananaskis Country
Banff-Yoho-Kootenay National Parks
Waterton Lakes National Park
(A map of the regions involved can be found here.)
