Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Dec 8th, 2013–Dec 9th, 2013

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, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Purcells.

Confidence

Fair - Due to the number of field observations

Weather Forecast

The strong arctic high will gradually start to break down. Weak frontal waves will cross the interior regions, bringing some cloud cover and light snowfall amounts.Monday: Mix of sun and cloud. Alpine temperatures show a high of -14. Ridgetop winds will blow moderate from the West. Tuesday: Cloudy with some sunny periods. Alpine temperatures show a high of -13. Ridgetop winds will blow light from the West. Snow amounts near 5 cm.Wednesday: Cloudy with sunny periods. Alpine temperatures show a high of -11. Ridgetop winds will blow light from the West. Snow amounts 3-5 cm.

Avalanche Summary

In the Northern part of the region a natural wind slab, size 1 was reported on a NW aspect. Additionally numerous size 1 loose dry avalanches from NW aspects were easily rider triggered. Loose dry avalanches are small, but they may be consequential if you're caught or pushed into depressions or off cliffs. Watch your sluff, and deek out to the side to escape.

Snowpack Summary

Strong NE winds after the storm have caused reverse loading and wind slab formation on SE through W aspects on open slopes and behind terrain features.Widespread surface hoar development and surface facetting exists. Snowpack depths at treeline vary across the region, averaging 70-110 cm. In the Southern part of the region there is 40-70cm of new snow over the late-November surface hoar/ crust/ facet interface that may be reactive, especially in sheltered northerly aspects where the surface hoar was better preserved.In the Northern part of the region the lower/mid snowpack is fundamentally weak, composed of an early season crust (more prevalent on north aspects) and weak faceted crystals above and below the crust. This persistent slab may be stubborn to trigger, but if triggered have high consequences. 

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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.