Avalanche Forecast

Issued: Apr 9th, 2013 9:55AM

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

Avalanche Canada ghelgeson, Avalanche Canada

Summary

Confidence

Fair

Weather Forecast

Synopsis:  Precip amps up Tuesday night but should taper off by Wednesday mid-day. The trailing cold front brings freezing levels down slightly with no significant precipitation expected through the duration of the forecast period. Wednesday: Freezing Level: 1300m Precip: 5/10mm – 5/20cm. Wind: Mod, W/NWThursday: Freezing Level: 1000m Precip: Nil Wind: Strong, WFriday: Freezing Level: 1000m Precip: trace Wind: Mod, SW.

Avalanche Summary

Skiers continued to trigger avalanches to size 1.5 Monday. Most of these avalanches involve the new snow failing on the recently buried temperature crust on steep solar aspects.  A few natural avalanches to size 2.5 were observed, likely occurring on this same interface. 

Snowpack Summary

Recent snowfall amounts vary considerably with elevation due to fluctuating freezing levels. Some lee alpine areas may have accumulations over 50 cm. The new snow is sitting on a crust or moist snow depending on elevation. Dense new wind slabs are likely in exposed lee terrain at and above treeline. Most of the recent precipitation fell as rain or wet snow below 1700-1800 m. The upper snowpack at lower elevations has become isothermal from recent warm temperatures and rain.  A frontal system passes over the region Tuesday evening which should bring snow above 1500m.  Rain falling below treeline is unlikely to have much affect. Cornices are very large and could pop off with continued mild temperatures or during periods of sun.

Problems

Storm Slabs

An icon showing Storm Slabs
Tuesday evenings storm snow will hide dense wind slabs that formed on steep slopes immediately lee of ridge crests and in cross loaded features at upper elevations.  Storm snow avalanches may step down triggering the deeper wind slab.
Avoid previously cross loaded slopes at or above treeline, those that face NW-SE.>Use ridges or ribs to avoid pockets of wind loaded snow.>Be aware of the potential for step down avalanches due to the presence of old windslabs.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Valid until: Apr 10th, 2013 2:00PM