Avalanche Forecast
Issued: Dec 18th, 2019 3:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
cgarritty,
Avalanche Canada
The barrage of storms hitting the coast is not expected to bring much precipitation inland, but be prepared to choose more conservative terrain if new snow exceeds forecast amounts.
Summary
Confidence
Low - Forecast snowfall amounts are uncertain. Recent weather patterns have resulted in a high degree of snowpack variability within the region. Uncertainty is due to the limited number of field observations.
Weather Forecast
WEDNESDAY NIGHT - Cloudy with scattered flurries bringing up to 5 cm of new snow. Moderate to strong southwest winds.
THURSDAY: A mix of sun and cloud with flurries increasing overnight. Light to moderate south winds. Alpine high temperatures around -5.
FRIDAY: Cloudy with 10-15 cm of new snow from the overnight period and scattered flurries bringing another 5-10 cm of new snow. Light south winds. Alpine high temperatures around -3
SATURDAY: Mainly cloudy with isolated flurries and a trace of new snow. Light southwest winds. Alpine high temperatures around -6.
Avalanche Summary
Observations are limited in this region, though there was a MIN report of several small human triggered avalanches around the Coquihalla Summit area on Saturday after only 20 cm of new snow had accumulated. Click here to read the report.
By Sunday morning, there was up to 60 cm of new snow in the south of the region. In the absence of new observations, and given the avalanche activity that occurred as we reached 20 cm, it would be wise to choose terrain while assuming a substantial storm slab remains sensitive to human triggering
There have been no avalanches reported in recent days in the northern part of the region. It is expected that reactive new wind slab and/or storm slabs have been forming at higher elevations. Areas that see more new snow from the ongoing series of storms will be the most concerning.
Snowpack Summary
A layer of new snow has begun to accumulate on the surface throughout the region, burying snowpack conditions that vary greatly from north to south within the region.
In the south, near the Coquihalla, up to 60 cm of snow from a storm last weekend likely sits on a weak layer of surface hoar. Avalanches began to be reported on this layer after it was buried only 20 cm deep, however new observations are limited. The middle of the snowpack contains a mix of hard crusts and facet/crust layers. Snowpack depths at treeline are about 100-150 cm.
In the north, near the Duffey Lake area, last week's storm only brought about 10-15 cm of new snow, which has seen significant wind redistribution and is now sitting on an already very thin snowpack. Snowpack depths at treeline are about 40-50 cm.
Problems
Wind Slabs
A recent succession of light snowfalls coupled with strong south to southwest winds are likely to have formed new wind slabs in higher elevation terrain. Snowfall amounts are expected to be highly variable, so use local observations to guide your terrain choices.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Conditions are highly varied from north to south within the region.
In the south, up to 60 cm of recent snow likely sits on a weak layer of surface hoar. Slabs formed on this layer may still react to human triggers, especially as loading from new snow increases strain on the snowpack.
In the north, light daily snowfalls have been incrementally adding load to an overall weak and thin early season snowpack. Concern exists for an emerging persistent slab problem in areas where deeper (15 cm or more) new snow amounts accumulate through Wednesday night.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 19th, 2019 5:00PM
