Avalanche Forecast

Issued: Mar 7th, 2018 4:20PM

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

pgoddard, Avalanche Canada

South Columbia.

Give cornices a respectful berth.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

THURSDAY: Cloudy. Around 10-15 cm snow. Treeline temperature near -4. Moderate southerly winds.FRIDAY: Mix of sun and cloud. Treeline temperature near -3. Light winds.SATURDAY: Mainly sunny. Treeline temperature near -1. Light winds.

Avalanche Summary

A natural cycle of size 1-2 loose snow avalanches was reported on Tuesday and Monday. A chunk of falling glacial ice triggered a size 3.5 slab on a north-west aspect. On Sunday, a skier triggered a size 1.5 persistent slab avalanche on a southwest aspect at 2100m. On Saturday a skier triggered a size 1.5 persistent slab avalanche on a northeast aspect at 1500m with a 1 m crown. Both were in the south of the region.

Snowpack Summary

Solar aspects have developed new sun crusts, which new snow may sluff easily on. Recent storm snow continues to settle. A couple of layers buried in mid-late February (down around 50-100 cm) are variably reactive, but both have the potential to create surprisingly large avalanches if triggered. Initially, these interfaces were most reactive on solar aspects, where they present as buried sun crusts. However, persistent slabs have been triggered on shady aspects too, where surface hoar and/or facets exist.Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with forecast warming, a surface avalanche stepping down, cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. Facets linger at the base of the snowpack.

Problems

Wind Slabs

New snow and wind may build new wind slabs. Stay well away from large looming cornices.

Be cautious as you transition into wind affected terrain.Extra caution needed around cornices with current conditions.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Persistent slabs are most likely to be triggered with a large load like cornice fall; or by a person in a thin or variable-depth snowpack spot.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Mar 8th, 2018 2:00PM