Avalanche Forecast
Issued: Jan 29th, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
istorm,
Avalanche Canada
Continued strong winds and a steady supply of new snow is driving the avalanche issues and elevated avalanche danger ratings. Stay cautious and moderate your objectives this week; conditions should improve for the weekend.
Summary
Confidence
High - The number, quality, or consistency of field observations is good, and supports our confidence. Uncertainty is due to the timing, track, & intensity of the incoming weather system.
Weather Forecast
Wednesday Overnight: Stormy night with continued strong southwest wind and snow.
Thursday: Wind easing and shifting around directions from southeast to southwest and possibly even northeast. Continued snowfall with another 10 cm possible; that should add up to as much as 30 or even 40 cm at Fraser over 3 days. Temperatures cooling to around -10 C.
Friday: Snowfall tapering and ending, wind diminishing to light or moderate from the south and southwest, and temperatures around -10 to -15 C.
Saturday: Continued cooling (temps around -15 C), easing winds (light southerly shifting to the north), and dry (no new snow). A trend that should continue into Sunday, with Sunday bringing clear(ish) sky.
Avalanche Summary
Tuesday's reports from Whitepass described fresh wind slabs and storm slabs were forming but not (yet) reactive to human traffic (in this case skiers) on small test slopes. Continued snow and especially wind will build them bigger and increase their sensitivity to triggering or failing naturally.
Snowpack Summary
Another storm is currently rolling through White Pass / Klondike Highway country with strong winds and snow. About 20 cm of new snow has fallen and there was previous fresh snow on the ground to blow around. In otherwords much of this snow is forming wind slabs or storm slabs at all elevations and aspects.
These slabs cover multiple layers of overlapping recent wind slab and old hard wind slab formations that existed previously in all but the most sheltered areas.
Snow depths at White Pass increased from around 100cm to 160 cm during the past week. Deeper locations (higher terrain west of the highway) have as much as 200 cm. It's reasonable to expect a thin snowpack composed mainly of sugary facets in the Wheaton Valley, and thinner wind-scoured alpine areas.
Terrain and Travel
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- Approach lee and cross-loaded slopes with caution.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Problems
Wind Slabs
Fresh snow combined with strong winds have formed a widespread storm slab / wind slab problem. Continuing stormy conditions and cooling temperatures are likely to increase the size and reactivity of slabs.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 31st, 2020 5:00PM
