Avalanche Forecast

Issued: Mar 8th, 2018 4:02PM

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

jsmith, Avalanche Canada

South Rockies.

Small fresh wind slabs reactive to human triggers are expected to form on lee features below ridgetops on Friday.

Summary

Confidence

High -

Weather Forecast

FRIDAY: Cloudy with flurries; 5-10 cm of new snow / Moderate to strong southwesterly ridgetop winds / Freezing level around 1500 m.SATURDAY: Mostly sunny / Light southwesterly ridgetop winds / Freezing level rising to around 1800 m.SUNDAY: Mostly sunny / Light southwesterly ridgetop winds / Freezing level rising to around 2000 m.

Avalanche Summary

Numerous loose wet avalanches to size 1.5 were reported on Wednesday. Explosive control work northwest of Elkford on Tuesday produced numerous size 3 persistent slab avalanches failing on facets near the base of the snowpack. The most notable results were on steep, rocky north aspects, and lower angled west aspects.

Snowpack Summary

Up to 10 cm of new snow on Thursday overlies sun crusts on solar aspects with generally better riding conditions on north and east aspects. The lower snowpack is generally weak with the primary concern being a combination of crusts and facets near the bottom of the snowpack that are widespread. The primary concern looking ahead towards the weekend and early next week is the potential of these deeper persistent weak layers becoming active by rapid warming of the snowpack through rising freezing levels and intense solar radiation.

Problems

Wind Slabs

Small fresh wind slabs reactive to human triggers are expected to form on lee features below ridgetops on Friday.

Watch for newly formed wind slabs as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 1.5

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.

Avoid steep convexities or areas with a thin or variable snowpackExtra caution needed around cornices with current conditions.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3.5

Valid until: Mar 9th, 2018 2:00PM