Archived

Avalanche Forecast

Mar 17th, 2015–Mar 18th, 2015

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: South Coast.

Winds have created a variable snowpack. Be alert to conditions that change with aspect and elevation.

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Generally light precipitation is expected on Wednesday, with the freezing level around 1700 m and winds light to moderate from the S to SW. Moderate snow is expected on Thursday and Friday (5-10 cm /day) above about 1800 m (rain at lower elevations). Winds are moderate to strong from the S to SW.

Avalanche Summary

A cycle of wind slabs and storm slabs (most size 1, up to size 2) was reported on Sunday and Monday. These failed naturally and were triggered remotely by skiers as well. Many were on north aspects. A snowmobiler also triggered an avalanche on Sunday (see https://bit.ly/19wEv36).

Snowpack Summary

Wind slabs and wind-affected surfaces are the main theme at the snow surface. Cornices may also be fragile. Older, buried wind slabs may be hard to spot. A crust/facet combo down 10-60 cm produces moderate, sudden results in snowpack tests. In the neighbouring Sea-to-Sky region, this layer has shown enough reactivity to call it a persistent slab problem. Maybe it is the same inland? Let us know. A second, deeper crust, marks the boundary with a lower snowpack that is reported to be generally well-settled and strong. Below treeline, the diminishing snowpack is trending isothermal (same temperature throughout).

Avalanche Problems

Wind Slabs

Touchy wind slabs have formed on many slopes. Cornices may be fragile and could break off further back from the edge than expected. Wind slabs could fail on a buried crust, creating surprisingly large avalanches.

Give cornices a wide berth when travelling on or below ridges.>Travel on ridgetops to avoid wind slabs on slopes below.>Be cautious as you transition into wind affected terrain.>Be aware of the potential for wide propagations due to the presence of a buried crust.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4