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Archived

Avalanche Forecast

Jan 25th, 2015–Jan 26th, 2015
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Northwest Coastal.

Continued wind, snow and warming will add more stress to buried weak crystals. Very large avalanches have been running from the alpine to valley bottom. Conservative terrain selection remains critical.

Confidence

Fair - Due to the number of field observations

Weather Forecast

The active weather pattern will continue as a fairly strong and moist southwest flow remains aimed at the region. Monday: Light to moderate snowfall, intensifying throughout the day / Light southwest winds intensifying to strong values throughout the day / Freezing level at 1200m  Monday night and Tuesday: Up to 30cm of snow / Strong southwest winds / Freezing level at 1200m    Wednesday: Light to moderate snowfall / Strong southwest winds / Freezing level at 1000m

Avalanche Summary

Recent observations have been somewhat limited, likely because of inclement weather. That said, storm slab avalanches to size 2.5 were noted in the north of the region on Saturday. With forecast weather, large storm slab avalanche activity is expected to continue with the potential to step-down to highly destructive persistent weaknesses. At lower elevations where precipitation is falling as rain, wet slab and loose wet avalanches remain a concern.

Snowpack Summary

Continued heavy snowfall (with rain below approximately 1500-1000 m) and extreme southwest winds have built fresh deep and dense storm slabs.  A rain crust and/or surface hoar layer buried mid-January is down around a metre. Recent reports mention that this weakness has become reactive with recent heavy loading and has been responsible for much of the recent large avalanche activity. The November crust near the bottom of the snowpack is generally well bonded, but may 'wake up' with intense loading this week. There is potential for isolated very large and deep avalanches.

Avalanche Problems

Storm Slabs

Continued heavy loading from snow and wind has created potent new storm slabs at higher elevations. Watch for increased reactivity in wind-exposed terrain. At lower elevations where rain has fallen, destructive wet slabs are also possible.
Good day to make conservative terrain choices.>Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

Over 100cm of recent storm snow overlies weak crystals which formed in early January. In recent days, very large avalanches were observed on these layers, and human triggering remains a very real concern.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>The new snow will require several days to settle and stabilize.>Be aware of the potential for large, deep avalanches due to the presence of buried crusts and/or surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 3 - 6

Loose Wet

The snowpack is saturated at elevations where rain has fallen. Pushy loose wet avalanches are a concern in steep terrain.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Even small avalanches may run a long ways under the current conditions.>Be cautious of wet sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3