Avalanche Forecast
Issued: Dec 13th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
bchristie,
Avalanche Canada
Continue to make conservative terrain choices. There has been very little break in storms for the snowpack to gain strength. Ongoing moderate winds continue to form rider triggerable slabs.
Summary
Confidence
Weather Forecast
A nice refresh of snow overnight is the most notable weather in the forecast period. The southeast corner of the region may see stronger wind . The cloud and intermittent light flurries are continuing to hang with us.
MONDAY NIGHT: Mostly cloudy. 3-12 cm snow expected. Moderate south winds, shifting to southeast. Freezing level around 500m.
TUESDAY: Partly cloudy. 0-5 cm of snow expected. Moderate southwest winds. Freezing level rising to 500-900m.
WEDNESDAY: Partly cloudy. Possible trace of snow. Light to moderate southwest winds, westerly at higher elevations. Alpine temperatures around -12
THURSDAY: Partly cloudy. Possible trace of snow. Light southwest wind, trending to strong west at higher elevations in the afternoon. Alpine temperatures around -11.
Avalanche Summary
Avalanche control in the north of the region produced small, skier triggered avalanches on north aspects.
On Sunday, a small, skier remote triggered avalanche was reported that failed on a reloaded bed surface near the base of the snowpack on a north aspect in the alpine. There were other deep failures reported in this region about a week ago. This information is spotty, but it is consistent with a deep persistent problem that may be difficult to trigger. We're not done worrying about this one yet.
Several size 1 and 2 natural avalanches were observed in the north end of the region on Friday. They seem to have failed within the storm snow.
Snowpack Summary
A refresh of snow overnight keeps the snowpack in a state of change. Where this new snow has been wind transported, it is more likely to form reactive slabs.
Recently, moderate to strong southwest winds redistributed 30-45cm of snow, forming reactive slabs that still need time to adhere to the rest of the snowpack.
Down 40-80cm, there is a 10-40 cm thick, solid melt freeze crust on all aspects up to 2400m (December 2nd).
Where the December 2nd crust does exist, facets may be forming on top, making this a layer to watch.
A late October facet/crust layer of concern sits at the bottom of the snowpack above 1900m. This layer has been reactive to human triggers, producing large avalanches. This layer is widespread and will likely continue to be a layer of concern.
Snowpack depth at treeline is 115-200cm, with the deepest snowpack found near the Bugaboos.
Terrain and Travel
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Wind Slabs
Moderate to strong southwest to southeast winds have formed the recent storm snow into slabs that are deeper and more reactive in leeward features.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A widespread weak layer of facets and depth hoar exists at the base of the snowpack above 2200m.
Avoid thin and rocky start zones where this layer may sit closer to the surface, and big open slopes capable of producing large avalanches.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Dec 14th, 2021 4:00PM
