Avalanche Forecast
Regions: Haines Pass.
Triggering a buried weak layer remains possible. Watch for warming-related problems as the day heats up.
Confidence
Moderate
Avalanche Summary
We haven't received reports of avalanche activity for the past few days, but check out this MIN that discusses whumpfing. The latest avalanche activity on the weak layer described in the Snowpack Summary occurred on Saturday.
Looking forward, it remains possible for humans to trigger this weak layer. Warming-related problems such as wet loose, wet slab, and cornice releases will also increase with daytime warming. Small storm-related problems could develop on Sunday.
Snowpack Summary
Sun-exposed slopes have a surface melt-freeze crust that turns moist during daytime warming. Shaded alpine slopes have a settled snow surface with potential surface hoar growing on top. Sunday's snow will accumulate on these surfaces.
A layer of surface hoar or facets associated with a crust may be found about 30 to 70 cm deep.
Cornices are large and looming at this time of year.
Weather Summary
Thursday Night
Clear skies. 5 km/h west ridgetop wind. Treeline temperature -1 °C.
Friday
Sunny. 10 km/h south ridgetop wind. Treeline temperature 2 °C. Freezing level 1500 m.
Saturday
Partly cloudy. 10 to 20 km/h southeast ridgetop wind. Treeline temperature 2 °C. Freezing level 1500 m.
Sunday
Cloudy with 5 to 10 cm of snow. 10 to 20 km/h south ridgetop wind. Treeline temperature -1 °C. Freezing level 1100 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
- Be alert to conditions that change with elevation and sun exposure.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
Avalanche Problems
Persistent Slabs
A weak layer may exist around 30 to 70 cm deep in the alpine, which was likely the culprit of some large natural avalanches last weekend and recent whumpfing. Use caution and assess for this layer, particularly in high consequence terrain.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1.5 - 2.5
Loose Wet
Naturally triggered wet loose avalanches may occur in steep terrain during the heat of the day. Cornices also weaken with warming and could release naturally. These could step down to deeper layers, resulting in large avalanches.
Aspects: East, South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5