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Avalanche Forecast

Archived

Dec 6th, 2022–Dec 7th, 2022

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

Glacier.

New snow and moderate wind created fresh storm slabs at higher elevations. Shooting cracks and whumphing may indicate the storm slabs have stiffened, bumping the danger level up to Considerable.

Watch out for early-season/low snowpack hazards! The poor visibility and new snow increase the likelihood of striking unseen objects just below the snow surface.

Confidence

Moderate

Avalanche Summary

Limited avalanche observations have been reported. Expect sluffing in steep unsupported terrain features and soft storm slabs in exposed start zones in the Alpine and at Treeline.

Whumpfing and remote-triggering continue on small, unsupported pillows at treeline and below on the Nov 17 persistent weak layer, both in GNP and our nearest neighbors.

Snowpack Summary

10-20cm of new low-density snow overlies more low-density facetted snow and surface hoar on specific terrain features. The Nov 17th Surface Hoar is now buried 50-70cm below the surface. Thin, shallow early-season snowpack conditions still exist; we have roughly half the snowpack we did at this time last Winter!

Weather Summary

10-20cm of new snow is expected by Wednesday morning! Flurries are forecasted to continue through Wednesday with up to 5cm more by end of the day. Temperatures should remain cool, in the minus 10C range, and winds will be generally light gusting to moderate from the West. Flurries and cool temperatures are forecasted to continue throughout the week.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Loose avalanches may start small but they can grow and push you into dangerous terrain.
  • Watch for fresh storm slabs building throughout the day.
  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.