Avalanche Forecast
Regions: Tutshi, Wheaton, White Pass East, White Pass West, Yukon.
A persistent weak layer exists in certain terrain features in the alpine. Layers like this are unpredictable and hard to out-smart. This problem could be around for a while and an overly cautious approach to large, connected, north-facing alpine terrain is prudent at this time.
Confidence
Moderate
Avalanche Summary
A couple of large (size 2-3) persistent slab, human-triggered avalanches have been reported over the weekend. Avalanches have occurred near ridgetops in north-to-northeast alpine terrain. Both avalanches have shown an impressive capability of propagating large distances. Here is a link to the most recent human-triggered size 3 avalanche.
Uncertainty remains about the distribution and extent of the problem.
If you are out in the backcountry please consider filling out a Mountain Information Network report.
Snowpack Summary
In alpine terrain, recent winds have created a variety of wind-affected surfaces. New snow and wind will create thin wind slabs in exposed terrain features. Recently formed hard surfaces and surface crusts had new surface hoar and facets on top before being buried. This new layer should be monitored closely moving forward.
Persistent weak layers of surface hoar and/or facets exist in north facing alpine features behind ridge lines, creating a number of recent, scary human-triggered avalanches.
Below roughly 1700 m a widespread, supportive, melt-freeze crust is present, with moist snow below.
Weather Summary
Tuesday night
Cloudy with light snow, 2 to 5 cm. Treeline temperatures -5 to -10 C. Moderate northeast alpine winds.
Wednesday
Cloudy, no precipitation. Treeline temperature -15 to -20 C. Moderate northeast alpine winds.
ThursdayCloudy, no precipitation. Treeline temperature -15 to -20 C. Moderate alpine winds.
FridayA mix of sun and cloud. No precipitation. Treeline temperatures -15 to -20 C. Light northeast 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.
- Make observations and assess conditions continually as you travel.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Wind slabs may be poorly bonded to the underlying crust.
Avalanche Problems
Persistent Slabs
Buried weak layers continue to produce large, surprising avalanches in alpine terrain. Although uncertainty remains around the extent and distribution of this layer, the recent avalanche activity has been observed on steep, north to northeast terrain. Keep in the mind the potential for remotely triggered avalanches and how far these large avalanches can run into flatter terrain. Also keep in mind that stiff slabs can pull back into flatter terrain above them. These layers will be easier to trigger where the snowpack is thinner.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine.
Likelihood: Likely
Expected Size: 1.5 - 3
Wind Slabs
Small amounts of new snow could be deposited into small wind slabs in steep alpine features. This will be a reverse-loading pattern as winds are forecast to be from the north this week.
Aspects: South, South West, West.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 1 - 1.5