Avalanche Forecast
Regions: Little Yoho.
The benign weather over the last week has decreased natural avalanche activity and is making explosive triggering more difficult. However, the snowpack is still weaker than normal and forecasters don't have a lot of faith in the current snowpack.
Continued discipline in sticking to mellower terrain with low consequences is the most reliable method of reducing risk in these conditions.
Confidence
Moderate
Avalanche Summary
No new natural avalanches were reported or observed over the last few days. Local ski hills are still triggering both the persistent and deep persistent weak layers but it is taking larger explosives and they are getting fewer and smaller avalanches than last week.
Snowpack Summary
Some wind-affected snow on alpine and treeline ridgetops. 10-20 cm of softer surface snow sits over a denser mid-pack which has formed a slab over the weak facet layers below. The December 17 persistent layer of surface hoar/facets is down 25-60 cm and becoming less reactive. The November 16 deep persistent layer of facets, depth hoar, and/or sun crusts is found near the base of the snowpack with test results continuing to show sudden failures.
Weather Summary
A relatively benign few days before a windy system moves in on Thurs/Friday.
Tuesday: Partly cloudy skies with a few flurries. Treeline temperatures in the -5 to -10 range. Light SW alpine winds.
Wednesday: Clearing skies. Treeline temperatures starting ~ -15 and rising to -5. Light NE alpine winds.
Thursday: Increasing cloud with light flurries. Treeline temperatures starting ~ -15 and rising to -5. Alpin winds increasing to strong to extreme from the SW.
Terrain and Travel Advice
- Uncertainty is best managed through conservative terrain choices at this time.
- Use careful route-finding and stick to moderate slope angles with low consequences.
Avalanche Problems
Deep Persistent Slabs
The lower snowpack is comprised of very weak facets, with the mid and upper snowpack forming a slab over these facets at all elevations. This weak basal layer is fairly uniform across most of the terrain and has shown the potential for human triggering, long propagations and remote triggering.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1.5 - 3
Persistent Slabs
The December 17 layer of persistent weak facets that formed during the prolonged deep freeze in early December is down 30-60 cm. This layer appears to be gaining strength, but is still worth considering. If a failure initiates on this layer, it may step down to the deep persistent layers resulting in larger avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2