Avalog Join
Archived

Avalanche Forecast

Jan 22nd, 2018–Jan 23rd, 2018
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
2: Moderate
The avalanche danger rating below treeline will be moderate
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
2: Moderate
The avalanche danger rating below treeline will be moderate
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
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Northwest Inland.

Increasing winds will be driving slab formation at higher elevations on Tuesday. At sheltered elevations where surface hoar exists, storm snow is gradually settling into an overlying slab even without the effect of the wind.

Confidence

Moderate -

Weather Forecast

Tuesday: Cloudy with scattered flurries bringing 2-5 cm of new snow, increasing overnight. Moderate to strong southeast winds. Alpine high temperatures of -9.Wednesday: Mainly cloudy with continuing isolated flurries and a trace of new snow, continuing overnight. Light to moderate southeast winds. Alpine high temperatures of -6.Thursday: Cloudy with continuing scattered flurries bringing 2-5 cm of new snow. Light southeast winds. Alpine high temperatures of -10.

Avalanche Summary

Reports from Saturday included one remotely (from a distance) triggered Size 1.5 wind slab releasing from a steeper northwest-facing slope at around 1500 metres. The slab depth was 40-60 cm.Friday's reports showed a notable increase in persistent slab activity at lower elevations in the Howson Range. In this area, three Size 2 releases failed on steeper terrain with remote triggers on the mid-December weak layer, found 50 cm below the surface. Another report from last week mentioned numerous natural storm slab releases from Size 1-2 north of Kispiox. These were suspected to have released over a layer of surface hoar that may not be widely distributed.Looking forward, our storm slab problem is diverging into more distinct wind slab problems at higher elevations and more isolated storm slab over surface hoar issues at mid elevations. Lower elevations have become an increasing concern in areas where the upper 50 cm of the snowpack has settled into a slab over the persistent mid-December weak layer.

Snowpack Summary

Recent light snowfalls have gradually brought about 20-30 cm of new snow to the region. The new snow has buried a temperature crust that exists well into the alpine. There are also reports of more isolated pockets of surface hoar beneath the new snow at lower alpine and treeline elevations. While its distribution is uncertain, this surface hoar remains an ongoing concern as the overlying storm snow settles into a slab above it.Below the new snow interface, deeper weak layers in the snowpack include a few crusts and surface hoar layers that formed in early January and December. Most recent reports suggest the snow is well bonded to these layers, but recent persistent slab activity over a surface hoar and facet 'combo' at low elevations suggests that a dangerous persistent slab problem may be developing as the mid and upper snowpack consolidate into a stiffer slab over this layer.

Avalanche Problems

Storm Slabs

Storm slabs have formed over widespread temperature crusts and more isolated pockets of surface hoar. Slabs are likely to be touchiest where surface hoar is buried as well as in the immediate lee of ridgecrests and exposed terrain features.
Use ridges or ribs to avoid steep pockets of wind loaded snow.Sheltered openings at mid elevations are likely areas for surface hoar to be preserved.Whumpfing, shooting cracks and recent avalanches are all strong indicators of unstable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

Recent reports have shown touchy persistent slab conditions developing at lower elevations in deeper snowpack areas of the region. Avoid the trap of lowering your guard below treeline - especially around steep rolls in sheltered openings.
Touchy persistent slab conditions have recently been observed in the Howson Range.Watch for signs of instability such as whumpfing, or cracking at lower elevations.

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1.5 - 2.5