Avalanche Forecast
Issued: Dec 14th, 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
Adopt a conservative approach to choosing terrain, and avoid thin, rocky start zones. The snowpack appears to be gaining strength, but some persisting weak layers could still be reactive to a rider's weight.
Summary
Confidence
Weather Forecast
The cloud and intermittent light flurries are continuing to hang with us, with some possible clear periods on the drier, east side of the mountain range. The southeast corner of the region may see stronger winds at treeline and above.
TUESDAY NIGHT: Mix of sun and cloud, clearer on the eastern slopes. 0-5 cm of snow expected. Moderate southwest winds. Freezing level falling to valley bottom.
WEDNESDAY: Mix of sun and cloud, clearer on the eastern slopes. Possible trace of snow. Light to moderate southwest winds, westerly at higher elevations. Alpine temperatures around -12
THURSDAY: Partly cloudy. 0-2 cm of snow expected. Light southwest wind, trending to strong northwest at higher elevations in the afternoon. Alpine temperatures cooling to around -14.
FRIDAY: Clearing with isolated clouds. No new snow expected. Light southwest winds, trending to strong northwest in the alpine. Alpine temperatures around -11 with a possible temperature inversion setting up.
Avalanche Summary
No new natural avalanches were reported.
Yesterday, avalanche control in the north of the region produced very small avalanches in the storm snow, and on Monday, 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.
Snowpack Summary
Other than some strong southwest alpine winds potentially forming new windslabs, the snowpack likely remains fairly unchanged from yesterday.
Variable snowfall over the region Monday night added up to 15cm of low density snow to the top of the snowpack. This snow fell with mostly light winds, so there should have been very little new slab formation.
Recently, moderate to strong southwest winds redistributed the previous storm's snow over the early December rain crust. This crust should be a very obvious feature 40-80 cm down from the snow surface. It is 10-40 cm thick, and can be found on all aspects up to 2300m.
This thick crust is likely to encourage facet formation above and below itself, so it will remain 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
- Use conservative route selection and resist venturing out into complex terrain.
- Be alert to conditions that change with elevation and wind exposure.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Wind Slabs
There are a few layers of wind slab overlying the early December rain crust. Any avalanche that starts in these wind slabs has the potential to step down to another windslab, or right to the rain crust.
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 15th, 2021 4:00PM
