Avalanche Forecast

Issued: Dec 19th, 2018 5:01PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada kdevine, Avalanche Canada

Natural avalanche activity has tapered off to some degree, but human triggered avalanches remain likely. Conservative terrain selection is recommended.

Summary

Confidence

Moderate.

Weather Forecast

WEDNESDAY NIGHT: Mainly cloudy with isolated flurries, southwest winds, 20-40 km/h, alpine low temperature near -4°c, freezing level 1000m. THURSDAY: Cloudy with flurries beginning mid to late afternoon, 5-10 cm, southwest winds, 20-40 km/h, gusting to 60 km/h, alpine high temperature near -1°c, freezing level 1400m. FRIDAY: A mix of sun and cloud, west winds, 20-40 km/h, gusting to 80 km/h, alpine high temperature near -3°c, low temperature near -12°c, freezing level 1100m. SATURDAY: Cloudy with sunny periods and isolated flurries, southwest winds, 10-30 km/h, alpine high temperature near -8°c, low temperature near -13°c.

Avalanche Summary

Numerous natural and explosives triggered avalanches to size 2.5 were reported in the region on Wednesday. Many of these were up to 100 cm deep. A notable avalanche on Wednesday was a size 3.5 explosives triggered avalanche in which the explosives were placed on a cornice. When the cornice failed, it triggered a 200 cm deep slab that failed on the crust at the base of the snowpack. This avalanche occurred on a northeast aspect at approximately 2000m .On Tuesday, natural storm slab avalanches in alpine terrain and numerous human triggered size 1 avalanches on small steep slopes were reported in the region. On Saturday, a group of skiers remotely triggered a size 2 avalanche on a northeast facing slope at treeline in the Corbin area. The skiers were in dense trees and the avalanche released roughly 60m above them. One skier was fully buried and the group successfully extricated them without significant injuries. For full MIN incident report follow this link.

Snowpack Summary

40-50 cm of recent snow has formed fresh storm slabs. The precipitation fell as rain below 1500m, leaving moist snow on the surface. Roughly 40-90 cm of snow now sits above a weak layer composed of large surface hoar (feathery crystals), facets (sugary snow), and/or sun crusts. There have been numerous signs over the past few days that this layer remains weak, such as remote triggering from low angle terrain and wide propagations in avalanches. Several other weak layers have been observed in the lower snowpack such as early season crusts with weak facets.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs are primed for human triggering, especially on steep and wind loaded slopes.
Use conservative route selection, choose moderate angled and supported terrain with low consequence.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
A widespread weak layer is being stressed by the new snow and has the potential to produce large, destructive avalanches.
Remote triggering is a concern, watch out for adjacent slopes.Avoid areas with overhead hazard.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Dec 20th, 2018 2:00PM