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Avalanche Forecast

Archived

Dec 3rd, 2022–Dec 4th, 2022

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

Regions

Glacier.

Triggering of the November 17th persistent weak layer remains possible in isolated terrain features. Assess the snowpack carefully before stepping out into large open slopes, especially around treeline.

Confidence

Moderate

Avalanche Summary

On Saturday Lone Pine produced a size 2 glide crack release which ran into the fan. Several other avalanches occurred up to size 2 out of steep, rocky terrain.

Reports of whumpfing and remote triggering of small unsupported pillows below tree line on the Nov 17 persistent slab continue.

Snowpack Summary

Surface snow is faceted due to the cold temps. The Nov 17 persistent slab (surface hoar 5-30mm, facets, and crust) is down 50-80cm with the largest surface hoar present on sheltered slopes at treeline and below.

Snowpack depth is still variable (~120cm at treeline), early season hazards remain a concern.

Weather Summary

Sunday will see a rise in temperature as a warm airmass passes through the region. Expect an alpine high of -5, mainly sunny skies, and light ridgetop winds.

Return to cooler temps and moderate winds by Monday evening. A small amount of snow is forecasted for Tuesday.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Problems

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.

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.