Avalanche Forecast

Issued: Jan 30th, 2016 7:07AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Persistent Slabs and Storm Slabs.

Avalanche Canada pmarshall, Avalanche Canada

The chances of triggering a slide may have decreased, but the consequences if triggered could be disastrous. Conservative terrain selection remains critical.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Sunday: Cloudy with a chance of flurries and sunny breaks late in the day. The freezing level is near 600-800 m. Winds are generally light. Monday: A mix of sun and cloud with a chance of flurries. The freezing level is near 400 m and ridge winds are light or moderate from the NW. Tuesday: A mix of sun and cloud with a chance of flurries. The freezing level is near 400 m and ridge winds are light or moderate from the NW.

Avalanche Summary

There were no new reports of avalanches on Friday; however, there is more evidence of a fairly widespread natural cycle earlier in the week. Many observers reported slabs up to size 3, mainly from steep open features at and below treeline. Observations are generally limited in the alpine but a couple observers noted a surprising lack of slab activity at higher elevations. Cooler and drier conditions should help stabilize the snowpack and reduce the likelihood of triggering. That being said, there is still potential for triggering lingering persistent weaknesses and producing very large and destructive avalanches.

Snowpack Summary

Generally 15-25 cm of lower density new snow overlies moist or wet snow, or previously wind affected surfaces in the alpine. Fresh wind slabs are likely in lee and cross-loaded features in the alpine and at treeline. The January 9th surface hoar/facet layer is down 70-150 cm in most places, and remains a concern on all aspects and elevations. Around the same depth you may also find a surface hoar/facet interface from around New Years. In the wake of the recent storm, there is a lot of uncertainty regarding the reactivity and distribution of this destructive persistent avalanche problem. Additionally, the snowpack will require time to adjust to the stress of heavy storm loading. A very conservative approach to mountain travel is still required.

Problems

Persistent Slabs

An icon showing Persistent Slabs
The likelihood of triggering deeply buried surface hoar layers should decrease over the next few days. However, the layer remains touchy in many areas and could surprise with disastrous consequences.
Be aware of the potential for extremely wide propagations.>Be aware of the potential for very large, deep and destructive avalanches due to the presence of buried surface hoar.>Be careful with low angle slopes that may not normally be a concern.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Storm Slabs

An icon showing Storm Slabs
It may be possible to trigger recently formed storm slabs in exposed lee terrain, which in turn could trigger more destructive persistent slab avalanches.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Jan 31st, 2016 2:00PM