Avalanche Forecast
Regions: Haines Pass.
Conservative terrain travel is recommended, as riders could trigger avalanches on buried weak layers. Watch your overhead exposure during the heat of the day.
Confidence
Moderate
Avalanche Summary
Riders saw evidence of recent large persistent slab avalanches and we received many reports of whumpfing (e.g., here). The avalanche observations add to the many natural and rider-triggered avalanches that released a week ago in alpine terrain. These weak layers may take some time to strengthen, meaning they may remain active to human traffic for the foreseeable future.
Please consider sharing your observations to the Mountain Information Network.
Snowpack Summary
Recent strong wind has produced wind affected snow in the alpine. Soft, settled snow may prevail in wind-sheltered terrain in the alpine. The snow surface on sun-exposed slopes will wet during the day and freeze into a hard melt-freeze crust overnight.
Weak layers of surface hoar crystals and/or faceted grains may be found around 30 to 70 cm deep. These layers may be associated with a hard melt-freeze crust above or below. These layers were the culprit of many large avalanches last week and remain unstable in snowpack tests.
Cornices are large and looming at this time of year.
Weather Summary
Wednesday Night
Clear skies. 20 km/h south ridgetop wind. Treeline temperature -7 °C.
Thursday
Clear skies. 20 to 30 km/h south ridgetop wind. Treeline temperature 0 °C. Freezing level rising to 1200 m.
Friday
Clear skies. 20 to 30 km/h southeast ridgetop wind. Treeline temperature 2 °C. Freezing level rising to 1500 m.
Saturday
Mostly cloudy. 10 km/h east ridgetop wind. Treeline temperature 2 °C. Freezing level rising to 1500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Choose conservative terrain and watch for clues of instability.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Cornice failures could trigger very large and destructive avalanches.
Avalanche Problems
Persistent Slabs
Weak layers of facets and/or surface hoar are buried around 30 to 70 cm deep. The layers are most prominent on alpine terrain features sheltered from the wind. Continued whumpfing and large avalanches are occurring on them.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood: Possible - Likely
Expected Size: 1.5 - 2.5
Loose Wet
Wet loose avalanches could occur on steep sun exposed slopes with daytime warming. Cornices are also large and may weaken.
Aspects: South East, South, South West, West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2