Avalanche Forecast
Regions: Field, Little Yoho.
Warm and windy on Friday. Although there is only a few cm of snow in the forecast, it is a significant change in the weather. There is uncertainty as to if and how this weather will impact the deeper weak layers but confidence is low.
Confidence
Moderate
Avalanche Summary
No new avalanches observed or reported in the Little Yoho region.
Snowpack Summary
10-20 cm of loose snow sits over a denser mid-pack which has formed a slab over the weak facet layers below - this snow will create new wind slabs in lee areas. The December 17 weak layer is down 25-60 cm and becoming much less reactive in tests. The November 16 deep persistent layer of facets and depth hoar is near the base of the snowpack, continuing to show sudden failures. Profile from Ogden Bench on Wednesday.
Weather Summary
Expect warm and windy on Friday with up to 5cm in Little Yoho and 1500m freezing levels so above freezing in places like Field. Expect strong SW winds 60-80km/h diminishing to 50-60km/h over the day.
Terrain and Travel Advice
- Uncertainty is best managed through conservative terrain choices at this time.
Avalanche Problems
Wind Slabs
With up to 20 cm of loose snow available for wind transport, Friday's increasing winds will create fresh, sensitive wind slabs in leeward areas. Expect this to build Friday.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 1.5
Persistent Slabs
The December 17 facets that formed during the prolonged deep freeze in early December are down 30-60 cm. Although the layer is gaining strength, it is still worth monitoring this layer in the deeper snowpack areas (west) where it is still reactive in the mid-pack.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1.5 - 2.5
Deep Persistent Slabs
The lower snowpack is comprised of weak facets, with a slab formed over this weakness at treeline and in the alpine. This weak basal layer is uniform across most of the region and has the potential for human triggering. With the warmer weather in the forecast, we are including this problem below treeline.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1.5 - 3