Avalanche Forecast

Issued: Apr 12th, 2014 9:30AM

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

jlammers, Avalanche Canada

Northwest Inland.

The timing of the this weekend's big warm-up is difficult to forecast. If Sunday ends up being the warmer day, Sunday's avalanche danger may be higher than posted, especially in deep snowpack areas.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

Sunday: Clear skies / Light and variable winds / Freezing level at about 2000mMonday: Clear with increased cloud late in the day / Light to moderate southwest winds / Freezing level at about 1500mTuesday: Overcast skies with very light precipitation / Light westerly winds / Freezing level at about 1300m

Avalanche Summary

At the time of publishing no new avalanches were reported, although I suspect natural loose wet and slab activity may have occurred with Saturday's warm temperatures. Below is a link showing natural avalanche activity over the past few days (sometimes photos speak louder than words):Hankin-Evelyn Trail-crew update

Snowpack Summary

Up to 30 cm of recent storm snow fell at upper elevations. At lower elevations rain saturated the snowpack and melt-freeze conditions exist up to 1200 m on all aspects. At higher elevations the new snow overlies a rain crust which exists to about 2000m. Strong SW winds have built thick wind slabs on leeward aspects and a poor bond may exist, especially where the buried crust exists. Two persistent weak interfaces exist deeper in the snowpack. The early March layer can be found down 75 - 100cm. The early February crust/facet/surface hoar combo is down 150 - 200cm. Particularly in deeper snowpack areas, these layers may have become overloaded by the recent storm. They should remain on your radar, and could become reactive with solar radiation and high freezing levels.

Problems

Wind Slabs

Recent storms have formed wind slabs in the lee of upper elevation terrain breaks. They may extra time to stabilize due to underlying weak layers.

Extra caution needed around cornices with current conditions.>Avoid cross loaded and leeward slopes at or above treeline.>The new snow will require several days to settle and stabilize.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Deep Persistent Slabs

Deep persistent avalanches would be very large and highly destructive. Possible triggers include cornice fall, a surface avalanche in motion, warming and intense solar radiation.

Minimize overhead exposure; avalanches triggered by warming and/ or cornice fall may run farther and faster then expected.>Be aware of the potential for large, deep avalanches due to the presence of buried facets and surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Loose Wet

Watch for loose wet avalanches with daytime warming on steep, sun-exposed slopes. Loose wet avalanches can be pushy and entrain mass quickly.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid slopes when temperatures rise and the surface snow becomes moist or wet and shows signs of instability, like pinwheels and natural avalanches.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Apr 13th, 2014 2:00PM