Avalanche Forecast

Archived

Feb 21st, 2015–Feb 22nd, 2015

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Glacier.

Cool temps and a moderate breeze will minimize the solar effect, but always use caution on solar aspects and around cornices when the sun shines.

Weather Forecast

A stubborn high pressure ridge sits over the provence today bringing clear, cool and dry conditions. Expect mostly sunny skies with moderate NE winds. Freezing level to 600m. The high pressure ridge will persists into early next week.

Snowpack Summary

Difficult travel and ski conditions below 1900m where a light dusting of new snow sits on a bulletproof crust. Ski Crampons are recommended. Above treeline, 20-25cm of light snow sits over the Valentines Day crust with soft wind slabs forming on all aspects. The mid-pack is well settled. Persistent weak layers down 1-1.5m are stubborn to trigger.

Avalanche Summary

No new avalanches were observed yesterday in the highway corridor. No signs on instability were observed by a field team on MacDonald West Shoulder.

Confidence

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.