Avalanche Forecast

Archived

Nov 28th, 2014–Nov 29th, 2014

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Glacier.

The Winter Permit System is in effect. Natural avalanche activity will decrease this weekend but conditions are still touchy. Don't let the sun lure you into bigger terrain. Human triggered avalanches are likely. Stick to simple, low angle slopes.

Weather Forecast

The warm, moist storm system that been hammering us will exit the region today. Rain should change back to snow, we may get another 10cm at higher elevations today, and winds should ease. Following the storm, an arctic high moves in and temperatures will plummet.. Saturday and Sunday will be clear and cold, with temps ranging from -18 to -28'C.

Snowpack Summary

Two layers of concern, the Nov 21 surface hoar/sun crust layer down ~ 90 and Nov 9 rain crust down ~110cm, are becoming reactive as the load on top of them increases. Snowpack tests in two locations, a south aspect and a north aspect, showed that these layers may be triggered by skiers and if triggered are likely to propagate into large avalanches.

Avalanche Summary

A large avalanche cycle occurred yesterday with natural avalanches occurring on all aspects, flattening the alder on avalanche fans. Along the highway corridor 28 size 2-2.5's, 9 size 3's and 2 size 3.5 avalanches were observed yesterday. As temperatures and freezing levels rose the avalanches became wet in character.

Confidence

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.

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.