Avalanche Forecast
Regions: Tutshi, Wheaton, White Pass East, White Pass West, Yukon.
An intense storm could trigger a natural avalanche cycle. Travel in avalanche terrain is not recommended.
Confidence
Moderate
Avalanche Summary
We haven't received reports of recent avalanche activity. Going forward, we anticipate a natural avalanche cycle over the day on Thursday as snow rapidly accumulates. Avoidance of avalanche terrain is recommended until the storm calms down and the snowpack has time to adjust.
Snowpack Summary
A substantial storm is forecast for Thursday, with forecast snow amounts of 30 to 50 cm by the end of the day. The snow will fall with strong southerly wind, which will make the deepest deposits in lee terrain features near ridges. This snow will fall on previously wind affected snow (sastrugi) in wind affected areas and faceted snow in sheltered features. The new snow may not bond well to these previous surfaces.
The storm will load a buried weak layer of surface hoar about 60 cm deep in Powder Valley, Tutshi, and Paddy Peak areas and up to 140 cm around White 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. To date this layer is has been most problematic in alpine terrain.
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
Wednesday Night
Cloudy with snowfall, accumulation 5 to 10 cm, 20 to 40 km/h south wind, treeline temperature -12 °C.
Thursday
Cloudy with snowfall, accumulation 20 to 40 cm, 60 km/h south wind, treeline temperature -6 °C.
FridayCloudy with snowfall then clearing, accumulation 10 to 20 cm, 40 km/h south wind, treeline temperature -5 °C.
SaturdayEarly morning snowfall then a mix of sun and cloud, accumulation 2 to 5 cm, 20 to 40 km/h east wind, treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Travel in alpine terrain is not recommended.
- Watch for fresh storm slabs building throughout the day.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Be aware of the potential for large, deep avalanches to run full path or even longer.
Avalanche Problems
Storm Slabs
A substantial storm is forecast to impact the region over the day on Thursday. Storm and wind slabs will rapidly build and they may not bond well with previous surfaces. A natural avalanche cycle is anticipated during periods of rapid loading.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Very Likely
Expected Size: 1 - 2.5
Persistent Slabs
Stormy conditions will load a weak layer of surface hoar and/or faceted grains around a hard crust, increasing the likelihood of an avalanche on this layer. The layer is buried around 60 cm in the eastern portions of the region and up to 140 cm around White Pass. This layer has recently 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 - Likely
Expected Size: 2 - 3