Avalanche Forecast
Issued: Dec 24th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
swerner,
Avalanche Canada
Recent wind loading may stiffen a thick slab that sits above buried, weak layers. This slab may be easily triggered by the weight of a person and initiate a large and destructive avalanche. A conservative mind-set is crucial with the current conditions.
Summary
Confidence
Weather Forecast
Friday: Mix of sun and cloud. Alpine temperatures near -3 and freezing levels 1100 m. Ridgetop wind moderate from the South.
Saturday: Chance of snow 5-10 cm. Alpine temperatures near -5 and freezing levels 1100 m.
Sunday: Cloudy with isolated flurries. Alpine temperatures near -5 and freezing levels 1100 m and dropping to valley bottom overnight.
Avalanche Summary
On Thursday a few explosive triggered size 1 avalanches were reported.
On Wednesday numerous storm slabs up to size 1.5 were triggered with explosives.
On Tuesday, a widespread natural avalanche cycle up to size 3 was reported from the lizard range.
Natural avalanche activity may taper off a bit but the snowpack remains primed for human triggering.
Please consider sharing your observations on the Mountain Information Network. Thank you to those that have already submitted this winter!
Snowpack Summary
30-50 cm of recent storm snow blanketed the region by Tuesday morning. Storm slabs will likely remain reactive to human triggers, especially where the wind stiffens the new snow. Deeper slabs will be found on lee slopes due to strong winds.
A persistent slab 80-130 cm thick now sits on the early December crust. This persistent weak layer, with facetted crystals and surface hoar crystals above and/or below it is reaching a tipping point.
Deeper in the snowpack are two hard melt-freeze crusts that formed in November that may have some weak crystals around them. This potential avalanche problem is dormant at this time, however; it remains on our radar.
Terrain and Travel
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
- Don't let the desire for deep powder pull you into high consequence terrain.
- Good day to make conservative terrain choices.
Problems
Storm Slabs
Storm slabs will likely be reactive and require patience and time to settle and stabilize. These may be extra touchy on lee slopes where wind loading has built deeper slabs. Loose-dry sluffing from steep terrain is likely, especilly when the sun comes out.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
This layer has reached a tipping point. Depending on elevation and aspect, 80-150 cm of snow currently sits above a buried crust from early December. Sugary, facets and surface hoar around the crust mean persistent slabs are likely reactive, especially to human triggers.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 25th, 2020 4:00PM
