Avalanche Forecast

Issued: Mar 14th, 2014 8:04AM

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

Avalanche Canada ccampbell, Avalanche Canada

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Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Saturday: Mainly cloudy with rain showers or scattered flurries bringing 5-10 cm depending on drainage. Mostly light westerly winds with strong gusts associated with snow flurry activity. Freezing levels as high as 2000 m. Sunday: Snow with 20 cm of accumulation depending on drainage. Generally moderate but gusty westerly winds. Freezing levels dropping slightly to 1800 m. Monday: Mostly cloudy with snow flurries bringing another 5-10 cm. Generally light westerly winds gusting with flurry activity, and freezing levels down to 1600 m.

Avalanche Summary

Reports from Thursday include a remotely triggered deep persistent slab avalanche with a heavy trigger in a low angle meadow. The slab released on the facet/crust weakness down 80-100 cm on a NW aspect at 2100 m.

Snowpack Summary

Recent storm and wind slabs are bonding poorly to buried surface hoar and facets particularly on sheltered slopes such as cut blocks, and crust on previously sun-exposed slopes. Warm temperatures and sun-exposure has been making these and deeper persistent slabs very sensitive to triggers at treeline elevations and below, and resulting in surface melt-freeze cycles as high as alpine elevations. The deeper facet/crust persistent weakness buried at the beginning of February, now down 100-150 cm, has been described by avalanche professionals as "very weird". Although widespread, it has been highly variable in terms of reactivity. Convective flurry activity has already accumulated 10-15cm of fresh snow in some drainages, which has likely blown into touchy wind slabs on leeward slopes.

Problems

Storm Slabs

An icon showing Storm Slabs
Dynamic conditions are changing with elevation and throughout the day, due to  warming, sun-exposure, snow flurries, and wind. Old storm (persistent) slabs lurk on sheltered low-elevation slopes, while fresh slabs may form on exposed lee slopes.
Make observations and assess conditions continually as you travel.>Choose conservative lines and watch for clues of instability.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 4

Loose Wet

An icon showing Loose Wet
Incoming storms are likely to be rain below 1800 m, further adding to the water saturation in the lower elevation snow-pack. Daytime heating and nighttime cooling are a critical part of the daily hazard evaluation.
Assess start zones carefully and use safe travel techniques.>Avoid steep, open glades in the forest.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Due to the high variability and significant potential consequences associated with a deeply buried facet/crust weakness, avalanche professionals have been maintaining a high level of caution and discipline.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Avoid unsupported slopes.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 15th, 2014 2:00PM