Avalanche Forecast
Issued: Feb 3rd, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
cgarritty,
Avalanche Canada
Seek out low density new snow that was sheltered from recent winds. An uptick in alpine winds toward the end of the day may begin to build new slabs at high elevations.
Summary
Confidence
Weather Forecast
Monday night: Clear. Light northwest winds, increasing into the morning.
Tuesday: Mainly sunny with cloud increasing over the day. Light to moderate west winds increasing over the day and overnight, becoming strong at ridgetop. Alpine high temperatures around -13.
Wednesday: A mix of sun and cloud with isolated flurries. Light to moderate west winds, becoming strong at ridgetop. Alpine high temperatures around -7.
Thursday: Mainly cloudy. Light to moderate west winds. Alpine high temperatures around -8.
Avalanche Summary
Reports from Friday showed small (size 1) wind slabs able to be triggered with ski cutting in the Castle area. More intense snowfall and wind throughout Saturday are likely to have spurred a natural avalanche cycle, focused in high elevation, wind-exposed areas.
On Thursday a cornice fall released a size 2 slab avalanche on the slope below on an east aspect at 2150 m.
On January 16th, a natural, size 2 wind slab stepped down to the deep persistent basal facets below a rock band, details here.
While avalanche danger is now low in areas where a new crust has capped the snowpack, potentially reactive wind slabs are likely to exist in the highest elevations as well as the east slope of the region where heavy snowfall combined with strong to extreme southwest winds during the storm.
Snowpack Summary
Variability in surface conditions is likely to be found in the region. In the Elk Valley and further west, an estimated 5-10 cm of snow sits above a solid new melt freeze crust which has capped the snowpack below about 2000 metres.
As a result of precipitation continuing as temperatures fell on Saturday night on the east slope of the range, roughly 20-30 cm of new snow, tapering with elevation, likely sits above a similar crust.
Above 2000 metres, suspected new snow amounts of 20-40 cm have been heavily impacted by strong to extreme southwest winds that affected the entire region. This new snow overlies previously wind affected surfaces.
A well consolidated mid-pack overlies a generally weak basal snowpack. The bottom 10-20 cm of the snowpack consists of facets and deteriorating crusts. While there has been little in the way of avalanche activity on this layer recently, it may be possible for a large load to trigger it in a shallow, rocky start zone.
Terrain and Travel
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Our new snow at higher elevations has seen extensive wind redistribution as a result of strong to extreme southwest winds. Expect to find increasingly deep and potentially reactive wind slabs as you gain elevation into the alpine. This problem is likely most pronounced on the east slope of the region.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 4th, 2020 5:00PM
