Avalanche Forecast
Issued: Dec 17th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
Tim Haggarty,
As a Pacific system arrives Saturday we expect modest snowfall amounts and a significant increase in the winds to raise avalanche hazard through the weekend.
Summary
Weather Forecast
A Pacific Low approaches the region Friday night. Ahead of the warm front, expect winds to increase reaching strong in the alpine as snow arrives Saturday morning. The current alpine temperature inversion will break down. Snow amounts range from 5 -15 cm favoring the divide and west before a high pressure system clears the region midday Sunday.
Snowpack Summary
15-25 cm of low density surface snow with extensive wind effect in the alpine. There is a Dec 2 rain crust present below 2200 m and down 40-60 cm with facets above and below. The Nov 5 crust/facet interface is found near the base of the snowpack and has been responsible for deep persistent slabs. Snowpack depths at treeline are from 120 to 180 cm.
Avalanche Summary
Ski patrols reported limited results with explosive work and skier control efforts today: mainly small slabs to sz 1.5 in lee features. A size 3.5 natural avalanche failing on glacier ice above the Bow Hut approach occurred in the last few days. This appeared to be triggered by wind loading and shows some of the uncertainty in the snowpack.
Confidence
Intensity of incoming weather systems is uncertain on Saturday
Problems
Wind Slabs
Only a few small wind triggered natural avalanches have been observed over the past several days but human triggering is still possible in some steep lee areas. With winds to increase and some new snow incoming, we would expect slab development.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 18th, 2021 4:00PM
