Avalanche Forecast

Issued: Apr 6th, 2015 10:43AM

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

ghelgeson, Avalanche Canada

Cariboos.

Warmth is the primary driver of avalanche hazard and the weather forecast calls for a steadily increasing freezing level over the next few days. Minimize your exposure to large slopes if the snowpack is becoming moist or wet.

Summary

Confidence

Fair

Weather Forecast

TUESDAY: Freezing level starting at 800m, rising to 1700m. Light SW winds at all elevations. No significant precipitation expected. Mostly clear skies.WEDNESDAY: Freezing level starting at 1400m, rising to 2000m. Light W/NW winds at all elevations. No significant precipitation expected. Clear skies.THURSDAY: Freezing level starting at 1500m, rising to 2200m. Light S/SE winds at treeline, moderate S winds at ridgetop. No significant precipitation. Clear skies.

Avalanche Summary

A very large (size 3) deep persistent slab failed naturally Sunday on a steep glacial feature at 2500m. It's presumed that this failed on early season basal facets. A small natural cornice fall was also observed.

Snowpack Summary

Recent convective snow showers have brought 15-30 cm of new snow. This snow remains dry on high elevation polar aspects but is quickly turning moist everywhere else. Cool night time temperatures are likely creating a thin surface crust. Moist snow exists underneath this most recent storm snow in most of the region.Two significant persistent weak layers composed of crust and facets exist in the snowpack. Mid-March is down 40 to 80cm below the surface and Mid-February is down 80 to 130cm. Avalanche activity on these weak layers has tapered off, but snowpack tests indicate that these layers may still be sensitive to triggering. Down at the bottom of the snowpack a weak layer of basal facets exists. Large loads like cornice/icefall or even sustained warming could initiate an avalanche on this very deeply buried weak layer.

Problems

Cornices

Steadily increasing temperatures for the next few days will likely make cornices more prone to failure. You do not want to be on top of or underneath these large and dangerously heavy pieces of snow when they collapse.

Cornices become weak with daytime heating, so travel early on exposed slopes.>When traveling in the alpine, be SURE you're on the ridge, and not on a cornice. These things demand your full attention.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

Human triggered persistent slab avalanches remain a concern. It's tough to say which features harbor a trigger-able weakness and which don't with any amount of certainty.

Stick to well supported terrain while avoiding potential trouble areas like rock outcroppings, convexities, and spots where the snowpack goes from thick to thin.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Loose Wet

Anytime previously dry/cool snow experiences the intense kiss of the spring sun, loose wet avalanches are likely. Most south and west facing slopes are probably done, but keep this problem in mind as you piece together travel plans.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 7th, 2015 2:00PM