Avalog Join
Archived

Avalanche Forecast

Feb 20th, 2016–Feb 21st, 2016
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
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

Regions: Northwest Coastal.

Watch for wind transport through the day and stay clear of freshly wind loaded features.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Monday

Weather Forecast

SUNDAY: snow starting in the afternoon with up to 10cm expected overnight, moderate westerly winds, freezing level of 1000m. MONDAY: cloudy with sunny breaks, moderate westerly winds, freezing level 1200m. TUESDAY: mainly sunny, light easterly southerly winds, freeing level 1200m.

Avalanche Summary

The only avalanche activity reported on Friday was skier triggered sluffing in steep terrain.  Earlier in the week there were numerous explosive triggered storm slab avalanches up to size 2, although I suspect these slabs are becoming less reactive with time.  At lower elevations (1500m and below), widespread loose wet avalanches were stepping down to size 2 wet slabs. In the far north, deeply buried persistent weak layers may still be reactive to large triggers such as a small avalanche stepping down or a cornice failure. On Thursday a skier triggered a size 2.5, deep persistent avalanche that released on basal facets on a SE aspect around 1700 m.

Snowpack Summary

40-90cm of settling storm snow sits above a melt freeze crust buried on February 12th which extends up to around 2000m elevation. The upper snowpack is reported to be bonding well to this crust. Moist snow may be found at lower elevations.  Recent wind has redistributed the surface snow at higher elevations forming wind slabs in lee features. The early January surface hoar/facet layer is down around 1m+ and remains a concern for commercial operations. This layer seems the most reactive in the north of the region but may still be a concern in the south as well. Shallow snowpack areas in the east and north of the region may have a weak base layer of facetted snow on or just above the ground.

Avalanche Problems

Storm Slabs

Recently formed storm slabs will continue to be reactive to rider triggering on Sunday. Wind loaded alpine features and south facing slopes when the sun comes out are likely to have the most reactive slabs.
Be alert to conditions that change with elevation. >Stay off recent wind loaded areas until the slope has had a chance to stabilize. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Deep Persistent Slabs

Buried weak layers remain a concern, especially in the far north of region.  Large avalanche can be triggered from thin spots and cornice releases, or smaller avalanches have the potential to step down.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar. >Dig down to find and test weak layers before committing to a big line. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 3 - 6