Avalanche Forecast

Issued: Apr 6th, 2015 10:48AM

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

South Columbia.

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 valley bottom, rising to 1800m. Light variable winds at all elevations. No significant precipitation expected. Clear skies in the morning, cloud cover increasing in the afternoon.WEDNESDAY: Freezing level starting at 900m, rising to 2000m. Light N/NE winds at all elevations. No significant precipitation expected. Mostly clear skies.THURSDAY: Freezing level starting at 1500m, rising to 2200m. Light SW winds at all elevations. No significant precipitation expected. Clear skies.

Avalanche Summary

Reported avalanche activity on Sunday was limited to power sluffing in steep high elevation terrain. On Saturday storm slabs ran to size 1.5 on NE through NW facing features between 1900 and 2700m. Loose dry avalanches to size 1.5 were reported from all aspects between 2000 and 2500m. A few size wet slabs were reported from southerly facing features between 2100 and 2500m. There were a couple noteworthy avalanches from last week. On Thursday a rider was partially buried in a size 2.5 wind slab on a north aspect at 2600m. On Wednesday, a naturally-triggered size 2.5 wind slab was observed on a NE aspect at 2500m. On that same day an ice fall triggered a size 3 deep persistent slab which failed at ground.

Snowpack Summary

Up to 20cm of dry snow may be hiding previously formed wind slabs on upper elevation slopes. These overlie a crust which varies in thickness with elevation. Sun may destabilize new snow and cornices. Below about 2000 m, loose moist snow makes up much of the snowpack underneath a surface crust. Persistent weak layers in the upper snowpack remain a lingering concern. The mid-March crust/facet layer is down around 60 cm. Down around 80 cm is the mid-February crust/facet/surface hoar layer. Both of these layers are slowly improving in strength, although it may still be possible to trigger one of these, causing a very large avalanche.

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