Avalanche Forecast

Issued: Mar 14th, 2014 8:10AM

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

Avalanche Canada ccampbell, Avalanche Canada

Check out the latest Forecaster Blog for insight on the current tricky conditions.

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: Cloudy with flurries bringing 10-20 cm 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

A recent natural cornice triggered Size 2.5 avalanche was observed Smith Basin area north of Elkford. As the snowpack warms during the day, loose wet surface avalanches as well as deeper persistent slab avalanches become sensitive to triggering.

Snowpack Summary

Recent overnight freezes have been stabilizing the wet upper snowpack, at least until the surface crust beaks down with daytime heating. This surface melt/freeze cycle is extending as high as alpine elevations on south aspects in the southern part of the region, but north of Elkford it's still winter-like with dry snow above 1800 m. 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 have been making these and deeper persistent slabs very sensitive to triggers. The deep 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. Weak basal facets exist in many areas, but without a large load, triggering now is unlikely.

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 slopes, while fresh slabs may form on exposed lee slopes.
Avoid freshly wind loaded features.>Be alert to conditions that change with elevation.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

Wet Slabs

An icon showing Wet Slabs
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 unsupported terrain below treeline especially if the snow is moist or wet.>

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.
Use conservative route selection, resist venturing out into complex terrain even if you observe no obvious signs of unstable snow.>Consider the consequences of the terrain if an avalanche steps down to a persistent weakness.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

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