Avalanche Forecast

Archived

Feb 19th, 2015–Feb 20th, 2015

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Little Yoho.

There are still concerns in wind-loaded areas and thin spots. There is a lot of variability with respect to aspect and elevation right now, so take some time to assess the snow where you are.

Weather Forecast

Friday - cloudy with light precipitation and moderate temps. Saturday - the wind shifts to north or northeast and will give us a brief taste of cold winter again.

Snowpack Summary

The snowpack is variable by aspect and elevation. Deep facetted weaknesses are still common. Westerly aspects have been wind-hammered and lee (east) aspects near ridge crests should be suspect. From treeline down, breakable melt-freeze crust transitions to bullet proof melt-freeze crust. Nasty.

Avalanche Summary

No new avalanches were reported today in Little Yoho.

Confidence

Due to the number of field observations

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.