Avalanche Forecast

Moderate - Uncertainty is due to extremely variable snowpack conditions reported through the region.

FRIDAY NIGHT: Increasing clouds and flurries. Light west wind up to 15 km/hr. Alpine low temperature -16 C. Freezing level valley bottom.

SATURDAY: Flurries starting overnight, up to 10 cm accumulation through the day. Increasingly gusty southwest wind, 25-45 km/hr. Alpine high temperature -5 C. Freezing level valley bottom. 

SUNDAY: Partly cloudy with sunny breaks. Northwest-west wind, 20-30 km/hr. Alpine high temperature -7 C. Freezing level valley bottom. 

MONDAY: Mostly cloudy with flurries, trace to 5 cm accumulation. Variable wind 10-20 km/hr. Alpine high temperature -9 C. Freezing level valley bottom. 

On Thursday, Dec 2 evidence of a natural avalanche cycle to size 3 occurring overnight Wed-Thurs was observed around the Golden area and north end of the forecast region. Through the day (and throughout the region), large storm slabs (size 2) and large deep persistent slabs (size 2-2.5) were triggered by explosives.

On Wednesday, Dec 1 a natural avalanche cycle was observed near Golden, including storm slabs and cornice failures to size 2 in north facing terrain. Explosive control work also produced several storm slabs. Nearby Glacier National Park observed a widespread natural avalanche cycle and produced up to size 3.5 avalanches with explosive control methods. 

Over the last week, numerous natural and explosive triggered storm slabs have been observed up to size 2 in wind effected terrain as a result of the heavy snowfall, rain and warm temperatures. 

Of note, several avalanches in the Toby Creek drainage are thought to have failed on a late November surface hoar layer. This is believed to be widespread in the Toby Creek drainage area, however data is sparse this early in the season and this layer may extend to other areas.

The snowpack is cooling and drying from the recent deluge of weather. With freezing temperatures a surface crust formed, which is now covered by 10-40 cm of snowfall from the past few days. 

The mid-November rain crust exists throughout the region below 1900m, around 60-100cm deep in the snowpack. A late October facet/crust layer of concern sits at the bottom of the snowpack above 1900m. This layer continues to produce results with explosives and in snowpack tests, and will likely continue to be an issue.

Around the Toby Creek drainage, a surface hoar layer sits down 30 to 60cm in sheltered features at treeline and below. We have limited knowledge of the distribution of this layer, however recent avalanche observations have shown this layer to be reactive. 

Average snowpack depth at treeline is 100-180cm, with the deepest snowpack found near the Bugaboos. 

• Be alert to conditions that change with elevation and wind exposure.
• Carefully monitor the bond between the new snow and old surface.
• Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
• Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
• In times of uncertainty conservative terrain choices are our best defense.