Avalanche Forecast

Issued: Apr 7th, 2013 9:29AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Cornices and Loose Wet.

Peter, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

Synopsis: A brief ridge of high pressure will result in drier conditions and sunny breaks on Monday. The next system arrives on Tuesday bringing moderate precipitation through Wednesday morning. Monday: A mix of sun and cloud. The freezing level climbs from near valley bottom to 1200 m during the day. Winds are light rising to moderate from the south in the evening. Tuesday: Moderate precipitation – 15-25 cm. Winds are strong from the south. The freezing level is around 1200-1400 m. Wednesday: Precipitation tapers off during the day. Winds ease to light from the southwest and temperatures cool a couple degrees.

Avalanche Summary

Widespread loose snow sluffing was reported in steep terrain at and below treeline on Saturday. Isolated small skier triggered slab avalanches were also reported.

Snowpack Summary

15-25 cm of new snow sits on a melt-freeze crust at most elevations. Reports suggest the new snow is not bonding well to the underlying crust. Pockets of wind slab have develoedp in exposed lee terrain and cross-loaded gullies. 30 - 60 cm of snow overlies a crust, old wind slabs or surface hoar layer buried on March 9th. The distribution of the surface hoar is also highly variable and it does not exist in every drainage. I would still remain cautious and continue to dig and test before diving into my line. Deeper in the snowpack, basal facets may resurface as a concern with continued mild temperatures.Cornices have become well-developed and could easily become unstable during periods of warm weather or direct solar radiation.

Problems

Wind Slabs

Thin new wind slabs are likely in exposed lee terrain and cross-loaded features. Triggering may be possible in steep terrain.

Be cautious as you transition into wind affected terrain.>Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

Large cornices may be weak and fall off naturally during warm temperatures or from increased loading.

Give cornices a wide berth when travelling on or below ridges.>

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 6

Loose Wet

Loose wet avalanches are possible in steep open terrain if the sun appears.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Apr 8th, 2013 2:00PM