Avalanche Forecast
Issued: Mar 29th, 2012 10:43AM
The alpine rating is Wind Slabs, Loose Wet and Deep Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Due to variable weather conditions
Weather Forecast
A continued low over the Gulf of Alaska will whirl a series of convective systems through the southern part of the province, bringing residual dribs and drabs of those systems to the northern regions. Friday: Snow amounts 5-10 cm. Ridgetop winds light from the SW. Alpine temperatures near -4. Freezing levels 1200m. Saturday/Sunday: The weekend will continue with quite the mixed bag of unsettled, spring-like convective weather. Expect bands of fast moving clouds, light precipitation, and periods of sun in the afternoons. Freezing levels look to behave at 1000-1100 m during the day, then falling to valley bottom at night.
Avalanche Summary
Natural avalanche activity seems to have tapered off over the past couple days. Most recent reports are of loose wet slabs (unknown size) below 1400 m. I suspect weather limited most operations from the field.Earlier this week the region saw many large cornice falls on N-E slopes. These did trigger smaller size 1-2 avalanches, but nothing stepped down to the deep persistent layer. This is good. Yet I wouldn't' rule out the potential, as we saw that layer reactive only 6 days ago. Numerous loose wet avalanches were also reported on Monday on various aspects, running up to size 2.
Snowpack Summary
Recently formed, variable wind slabs exist in the alpine, treeline, and open areas below treeline. These can be found on lee slopes, and behind terrain features. Over the past several days, spring-like conditions have influenced the snowpack. Solar radiation has led to moist surfaces on sunny slopes up to ridgetop during the day, and other aspects moist below 1500 m with limited crust recovery overnight. Cornices have grown large and may become unstable under sunny skies; they may act as a large trigger on slopes below. A well settled, consolidated slab overlies a persistent weak layer that was buried in early February. Now 1-2 m below the surface, these weaknesses include surface hoar, facets or crusts. Concern still exists potentially for deep and destructive releases at this interface. This may be a low probability, high consequence problem that may require a large trigger.
Problems
Wind Slabs
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Aspects: North, North East, East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 30th, 2012 9:00AM