Avalanche Forecast
Issued: Jan 2nd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
cgarritty,
Avalanche Canada
The storm rages on. Sunday will be another good day to avoid avalanche terrain as another 30-50 cm of new snow is added to the snowpack
Summary
Confidence
Weather Forecast
SATURDAY NIGHT: Cloudy with continuing snowfall bringing 15 to 25 cm of new snow. Strong southwest winds.
SUNDAY: Cloudy with continuing snowfall bringing 20 to 30 cm of new snow, easing overnight. Strong southwest winds, easing overnight. Alpine temperatures around -4.
MONDAY: Cloudy with increasing flurries bringing 5 to 10 cm of new snow, continuing overnight. Moderate to strong south winds. Alpine high temperatures around -6.
TUESDAY: Cloudy with flurries bringing about 10 cm of new snow, continuing overnight. Strong south winds. Alpine high temperatures around -4.
Avalanche Summary
New snow was very reactive to skier traffic on Friday and almost certainly again on Saturday as snowfall continued. These touchy conditions are expected to ramp up into (or continue) a natural avalanche cycle through Saturday night.
Very large avalanches may result as snow piles up and loads the buried weak layers described in the snowpack summary. As of Saturday morning at least one large avalanche was reported to have stepped down to a deeper weak layer. Avalanches will continue to be very likely to be triggered naturally and/or by riders on Sunday.
Snowpack Summary
A hefty storm is impacting the region this weekend. 35 to 50 cm of snow has accumulated so far and upwards of 40 cm more snow may accumulate by the end of the day on Sunday. Storm slabs are expected to be rapidly forming. The snow is falling with strong southwest wind, which is likely also rapidly forming wind slabs in exposed terrain.
All of this snow is loading two weak layers of feathery surface hoar, now an estimated 60-100 cm deep. The deeper surface hoar was reported as being widespread prior to burial and the upper layer may sit on a melt-freeze crust from warm air on Boxing Day and/or from sunny skies.
Around 150 to 200 cm deep, a hard melt-freeze crust from early December may have weak and sugary faceted grains around it. These weak layers are likely the culprit of avalanche activity last weekend in the Nass Valley, Sterling, and Beaupre riding areas.
The early-November melt-freeze crust is over 200 cm deep and may have faceted grains above it in parts of the region, particularly in the north. The last reported avalanche activity was near Ningunsaw on December 11.
Terrain and Travel
- Travel in alpine terrain is not recommended.
- Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
- Avoid exposure to overhead avalanche terrain, avalanches may run surprisingly far.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
Problems
Storm Slabs
Storm totals may reach 100 cm by Sunday afternoon, with the most snow expected in the west of the region. Storm and wind slabs are building rapidly and they are loading buried weak layers. If it isn't already underway, a natural avalanche cycle is expected to begin Saturday night, meaning very dangerous conditions will persist through Sunday.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Numerous weak layers may exist in the top half of the snowpack, including surface hoar and faceted grains over a melt-freeze crust. These layers were recently triggered in riding areas north of Terrace. The likelihood of avalanches involving these layers will be heightened during and immediately after this stormy period.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 3rd, 2021 4:00PM
