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Avalanche Forecast

Archived

Dec 4th, 2022–Dec 5th, 2022

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.
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.

Small pockets of wind slab may be lingering in the alpine.

Confidence

High

Avalanche Summary

On Sunday several sz 1-1.5 solar-induced loose dry avalanches occurred within the surface facet layer out of steep, rocky terrain. On Saturday Lone Pine produced a size 2 glide crack release which ran into the fan.

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

Expect valley cloud for most of the day as the inversion layer and warm air aloft give way to colder temperatures again. The alpine high will be -12, winds will be from the West at 15-25km/hr.

Small amounts of snow over the next few days.

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.