Avalanche Forecast

Issued: Feb 12th, 2015 8:48AM

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

pgoddard, Avalanche Canada

South Columbia.

Conditions vary across the region. In some places, there is still a real possibility of triggering a surprisingly large avalanche.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Temperatures are very warm (freezing level peaking near 2800 m) on Thursday and Friday, before cooling on Saturday with the passage of a cold front. Light precipitation is expected on Friday, followed by 5-10 mm precipitation on Saturday. This tapers to flurries on Sunday. Winds are light to moderate SW, changing to NW on Saturday as the front passes through.

Avalanche Summary

Loose wet avalanches to size 2 were triggered naturally and by skiers on Wednesday. These occurred on steep faces that caught some sun and at low elevations where the snowpack is water-soaked. A size 2.5 persistent slab failed on a steep shallow rocky feature at 2500 m, approximately 1 m deep. Cornices also collapsed naturally and with explosives.

Snowpack Summary

Recent storm snow appears to be settling and bonding with warm temperatures. SW winds have created areas of wind slab on some alpine lee features. Keep your eyes open for cornices, which may be sensitive to collapsing with the warm temperatures. The late-Jan crust/surface hoar layer, buried up to a metre deep, remains a key concern. Triggering this could produce a surprisingly large avalanche. The mid-January surface hoar is typically down 80-120cm and is most likely to be triggered from thin or rocky snowpack areas; or perhaps with a cornice fall, or an avalanche stepping down. The mid-December weak layer is down over 120cm, but is generally considered unreactive.

Problems

Persistent Slabs

Persistent slabs are most likely to be triggered from thin snowpack areas, or with large triggers like cornice fall or an avalanche stepping down.

Avoid common trigger points like convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Wind Slabs

Wind slabs may be lurking on lee and cross-loaded features in the alpine. Cornices are weak with warm temperatures and may collapse.

Be cautious as you transition into wind affected terrain.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

Warm temperatures and drizzle have weakened the snowpack, especially at low elevations.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>On steep slopes, pull over periodically or cut into a new line to manage sluffing.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 13th, 2015 2:00PM