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Avalanche Forecast

Dec 4th, 2018–Dec 5th, 2018
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
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

Regions: North Columbia.

The snowpack appears to be gaining strength, but keep the persistent slab in mind when choosing terrain. Be skeptical of large treeline features and steep south facing slopes.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

TUESDAY NIGHT - Clear periods / light to moderate northerly winds / alpine temperature near -13WEDNESDAY - Sunny with cloudy periods / light southeast winds / alpine high temperature near -11THURSDAY - Sunny with cloudy periods / light southerly winds / alpine high temperature near -6, low temperature near -11FRIDAY - A mix of sun and cloud / light south wind / alpine high temperature near -5, low temperature near -7

Avalanche Summary

No new avalanches have been reported in the region.Although outside of the region, it is notable that three large avalanches have been reported recently in the South Columbia region between November 24 and December 1. It is likely that they ran on the October crust as they were essentially full depth avalanches. One occurred naturally, one was human triggered and the other was triggered with explosives.We currently have very few observations from within this region. Please post your observations to the Mountain Information Network (MIN).

Snowpack Summary

The primary concern in the snowpack is a layer of surface hoar (weak feathery crystals) and sun crust on steeper south facing slopes. This weak layer is down 30-50 cm and it is most prominent at treeline, but it may be found in sheltered alpine areas.At the base of the snowpack is a crust that formed in late October. There have been no recent reports of reactivity on this layer in the North Columbia, however there has been some avalanche activity on this layer in the South Columbia region over the past 10 days. Steep, rocky terrain, with a shallow snowpack are the most likely areas to trigger this layer.Total snowpack depths vary greatly with elevation. Recent reports show depths of 120-230cm in the alpine, 90-180 cm at treeline and 10-120 cm below treeline.

Avalanche Problems

Persistent Slabs

30-50 cm of snow sits on top of a weak layer of surface hoar (feathery crystals) and sun crust on steeper south facing slopes.
If triggered, the slab may step down to deeper layers resulting in large avalanches.Watch for signs of instability such as whumphing, cracking, and evidence of recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2