Avalanche Forecast
Regions:
Recent avalanches have shown an ability to propagate far and deep in the snow pack.
Large slopes are still a concern and are most likely to be triggered in thin rocky areas.
Confidence
Moderate
Avalanche Summary
No new avalanches were reported in the region on Monday. Backcountry users may see evidence of a large avalanche cycle from the weekend as they travel through the terrain. These avalanches may have occurred during last week's storm or due to solar input and elevated freezing levels through the weekend.
On Sunday, a suspected skier triggered avalanche was reported. This was a size 1 storm slab avalanche that likely occurred on Saturday.
If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.
Snowpack Summary
Last week's storm that delivered 50 cm of new snow to both passes has been heavily wind affected in the alpine with less wind affect at lower elevations where it is capped by a thin crust below 1300 m. In sheltered northerly aspects there is up to 20 cm of soft snow still hiding from the wind.
A buried weak layer of surface hoar can be found about 80 cm deep in Powder Valley, Tutshi, and Paddy Peak areas, 150 to 200 cm around White Pass and 80-200 cm deep in Haines Pass. This layer is most prominent on northerly slopes sheltered from the wind. On other aspects, this layer is a hard melt-freeze crust with weak facets around it. This layer has been most problematic in alpine terrain.
The remainder of the middle of the snowpack is consolidated and strong. Weak faceted grains are found near the base of the snowpack, particularly in thin snowpack areas.
Weather Summary
Tuesday Night
Mainly cloudy with scattered flurries, 5 cm accumulation. Strong southwest ridge top winds. Alpine temperature low -12°C. Freezing levels valley bottom.
Wednesday
Mainly cloudy with isolated flurries, 4-6 cm accumulations. Strong south ridge top winds. Alpine temperature high -9°C. Freezing levels 500 m.
Thursday
Partly cloudy with isolated flurries, 4 cm accumulations. Moderate southeast ridge winds. Alpine temperature high -8°C. Freezing levels 700 m.
Friday
Mainly cloudy with isolated flurries, trace cm accumulations. Light south ridge winds. Alpine temperature high -9°C. Freezing levels 500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
- Be carefull around freshly wind loaded features.
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Avalanche Problems
Wind Slabs
Hard wind slabs may still linger on north and west facing terrain features. Though natural avalanche activity has tapered off they remain possible to human trigger.
Observe the wind loading pattern in the area as you move through the terrain, southwest winds Tuesday will redistribute available snow into fresh wind slabs in lees through the day.
Aspects: North, North East, East, South West, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 2.5
Persistent Slabs
A weak layer of surface hoar and/or faceted grains around a hard crust sit in the mid snowpack. This layer is buried around 80 cm in the eastern portions of the region and up to 200 cm around White Pass and Haines Pass.
This layer has previously produced widely propagating avalanches in alpine terrain and it is capable of being remotely triggered from a distance. The most likely area for riders to trigger it is in wind-sheltered, north-facing terrain, and in rocky terrain where the snowpack is thin.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 2 - 3