Avalanche Forecast

Issued: Feb 17th, 2014 8:43AM

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

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Overnight and Tuesday: 3-5 cm more snow expected overnight with moderate Westerly winds. A brief break in the morning followed by another fast moving system with very strong Southwest winds and another 10-15 cm by Wednesday morning. Freezing level dropping to valley bottom overnight and rising to about 1500 metres during the day.Wednesday: Overcast with a chance of convective flurries and light Northwest winds. Freezing level at valley bottom.Thursday: Cloudy with a chance of broken skies and light Westerly winds.

Avalanche Summary

We continue to get reports of accidentally triggered and remote triggered avalanches. See the bottom left of the bulletin page for a list of reported avalanches for this region. I suspect that the storm slab is settling and becoming more cohesive. Forecast new snow and wind loading are expected to add a new load to this recent storm slab that may increase the sensitivity to human triggers and may result in natural avalanches.

Snowpack Summary

Another 20 cm of new snow has added to the recent storm slab that is now about 75 cm thick and is settling into a cohesive slab (one finger resistance). The layer of weak facetted (four finger resistance) snow that is below the storm slab has been reported as widespread on all aspects and at all elevations across the region. This is the classic firm slab over soft and weak layer that can allow for wide propagations and remote triggering. This problem may persist for days after the storm or even weeks. The next forecast storm on Tuesday night may overload the weakness and cause another natural avalanche cycle. Regardless, it will continue to load above the weak layer priming conditions for large slab avalanches. The mid snowpack is strong and supportive. A deep persistent layer of facets and depth hoar near the base of the snowpack has remained dormant to this point, but may become a concern with additional load and stress on the snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs
Forecast new snow and strong winds are expected to continue to add a new load to the storm slab. Natural avalanches and very touchy sensitivity to human triggers may result from this added load.
The new snow will require several days to settle and stabilize.>Minimize exposure during periods of heavy loading from new snow, wind.>Extra caution needed around cornices with current conditions.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Valid until: Feb 18th, 2014 2:00PM

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