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 10th, 2013–Dec 11th, 2013

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

Regions

Purcells.

Confidence

Poor - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Interior regions will start to see moderate amounts of snow, gradual warming and strong ridgetop winds as the warm front of the Pacific Frontal systems arrives on Wednesday.Wednesday: Cloudy. Snow amounts 5-10 cm. Alpine temperatures near -9. Ridgetop winds moderate from the West. Thursday: Cloudy with flurries near 4 cm. Alpine temperatures near -10. Ridgetop winds moderate, gusting strong from the West.Friday: Cloudy with snow mounts near 5 cm. Alpine temperatures -8. Ridgetop winds light from the SW. On Friday a weak ridge may stall precipitation later in the day, and bring some sunny breaks.

Avalanche Summary

No recent avalanche observations have been reported.

Snowpack Summary

Strong NE winds have reverse loaded and formed isolated wind slabs in the leeward side of SE through West aspects. Loose dry surface sluffing from steeper terrain may occur, so use caution near terrain traps like cliffs, and depressions.Widespread surface hoar development and surface faceting exists from the previous cold temperatures and is now getting buried by incremental snowfall amounts. 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 and depth hoar 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.