Avalanche Forecast
Regions: Tutshi, Wheaton, White Pass East, White Pass West, Yukon.
6:30 AM PST UPDATE: A weak layer of surface hoar is buried at a prime depth for human-triggering as well as large consequential avalanches.
The most activity has been noted on northerly alpine slopes, but until we gain more information about this layer riders should take a very cautious approach to avalanche terrain. Check out this MIN report from the Avalanche Canada field team on Friday.
Confidence
Moderate
Avalanche Summary
Numerous large (size 2-3) natural and human-triggered persistent slab avalanches have been reported in the past 3 days. These avalanches are failing on a weak layer of surface hoar with a crust below.
Snowpack Summary
In alpine terrain, recent winds have created a variety of wind-affected surfaces. Wind slabs remain in steep, lee terrain features and may be burying isolated pockets of preserved surface hoar. The surface hoar is reported to be roughly 50 to 80 cm down from the surface. Below roughly 1700 m a widespread, melt-freeze crust is present, with moist snow below.
Weather Summary
Sunday night
Becoming overcast, with flurries beginning in the early morning. Treeline temperatures -5 to -10 C. Moderate west alpine winds.
Monday
Cloudy, with flurries, 0 to 2 cm. Treeline temperatures -5 to -10 C. Moderate westerly alpine winds.
Tuesday
Cloudy, with flurries, 0 to 2 cm. Treeline temperatures -5 to -10 C. Light southwest alpine winds.
Wednesday
Cloudy with sunny periods, no precipitation. Treeline temperature -10 to -15 C. Moderate alpine winds.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- In times of uncertainty conservative terrain choices are our best defense.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
Avalanche Problems
Persistent Slabs
A weak layer of surface hoar overlying a crust is now buried 50-100 cm deep, a prime depth for human-triggering and large consequential avalanches. The most activity has been noted on northerly alpine slopes, but until we gain more information about this layer riders should take a cautious approach to avalanche terrain. Keep in the mind the potential for remotely triggered avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1.5 - 3
Wind Slabs
Be wary of isolated pockets of surface hoar buried by stiff wind slabs, in wind loaded, northeasterly alpine terrain. Recent avalanches have shown an impressive capability to propagate.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 3