Avalog Join
Archived

Avalanche Forecast

Dec 12th, 2022–Dec 13th, 2022
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
1: Low
The avalanche danger rating in the alpine will be low
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Glacier.

The recent low-density storm snow is settling out and showing increasing signs of slab properties. There is uncertainty of if/when the tipping point will be reached on the persistent weak layers, which would likely result in the wide propagating avalanches seen adjacent to Rogers Pass.

Assess the snowpack carefully before stepping out into committing terrain.

Confidence

Moderate

Avalanche Summary

Several loose dry avalanches up to size 2 from steep, rocky North facing terrain off Mt MacDonald.

Reports continue of small, unsupported pockets of soft slab failing on Dec 5 and Nov 17, mainly occurring around treeline and morainal features.

Snowpack Summary

Up to 40cm of settled snow now buries the Dec 5 layer, which consists of surface hoar, preserved stellars, facets, and a thin sun crust on steeper solar aspects.

The Nov 17th Surface Hoar is now buried 60-90cm and continues to produce sudden results in snowpack tests.

Weather Summary

A ridge of high pressure will maintain dry conditions over the region for the next few days. Light winds, Alpine highs in the -5*C to -9*C, and no snow for the week.

Terrain and Travel Advice

  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Avalanche Problems

Persistent Slabs

The Nov 17 and Dec 5 surface hoar are down ~75cm and ~35cm respectively, and most prevalent around tree line. These layers of surface hoar give 'sudden' results in snowpack tests; they have a propensity to propagate across continuous and broken features; and, they produce dramatic whumpfs in previously untraveled open glades.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Wind Slabs

45cm of recent low density snow is available for transport. Isolated pockets of surface slabs may be found in Alpine and open Treeline lee features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2