Avalanche Forecast

Issued: Mar 4th, 2018 4:01PM

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

mbender, Avalanche Canada

South Rockies.

Recent new snow combined with wind has promoted wind slab development as well as cornice growth. As the clouds part in the coming days remember that the sun packs a punch this time of year.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

MONDAY: Mix of sun, cloud and isolated flurries / Light to moderate west wind / Alpine temperature -9 TUESDAY: Mix of sun, cloud and isolated flurries / Light to moderate west wind / Alpine temperature -8 WEDNESDAY: Mix of sun, cloud and isolated flurries / Light southwest wind / Alpine temperature -8

Avalanche Summary

Over the past week there have been reports of both natural and skier triggered loose dry avalanches in steep terrain to size 1.5.

Snowpack Summary

10-25 cm of new snow falling Friday night, brings accumulated storm snow total to 25-40cm. This new snow covers previously wind-scoured, westerly slopes and old hard and soft wind slabs on leeward, easterly alpine and treeline slopes. Beneath these old wind slabs lies a well-settled mid-pack. The lower snowpack is generally weak with two primary concerns that are widespread:A widespread weak layer from mid-December composed of facets, crusts, and surface hoar that is 100-150 cm deep.A rain crust with sugary facets buried in late November near the bottom of the snowpack.

Problems

Wind Slabs

The recent new snow came in as fluff. There is now lots of new snow available to be transported into alpine and treeline lee terrain features with forecast west and southwest wind in the coming days.

Avoid exposure to steep, sun exposed slopes when the solar radiation is strong.Watch for signs of instability such as recent avalanches or shooting cracks.Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Deeply buried weak layers are lingering near the base of the snowpack. These layers are most likely to be triggered from thin or variable snowpack areas or with a large load like a cornice fall.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Avoid steep convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3.5

Valid until: Mar 5th, 2018 2:00PM