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Archived

Avalanche Forecast

Jan 24th, 2015–Jan 25th, 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
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
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
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 Inland.

Recent snowfall totals vary dramatically across the region. Pay close attention to localized conditions.

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

A steady pacific moisture stream is aimed at the North Coast, although the track of the system suggests the bulk of the precipitation will initially fall just to the south of the region. Sunday: Between 5 and 10cm of snow at higher elevations / Extreme southwest winds / Freezing levels at 1400m Monday: Up to 15cm of snow at higher elevations / Strong southwest winds / Freezing levels at 1300m Overnight Monday and Tuesday: 10-15cm of snow / Strong southwest winds / Freezing levels at 800m

Avalanche Summary

Periods of heavy snow or rain, strong ridge winds, and warming will probably tip off a natural avalanche cycle in parts of the region. We could see wet activity at lower elevations with storm/wind slabs where snow accumulates. There is also potential for deep persistent weaknesses to be overloaded producing isolated very large and deep slides.

Snowpack Summary

Continued snowfall has contributed to ongoing storm slab development. Warm temperatures have promoted rapid slab settlement, while rain has created wet loose surface snow at lower elevations. Southwest winds continue to build slabs on leeward slopes with cornices overhead in exposed treeline and alpine terrain. A recent report from the Ashman area mentioned whumpfs and other signs of instability associated with roughly 30 cm of recent snow rapidly settling into a slab under warm temperatures and significant wind. A surface hoar layer buried at the start of January may be around 40-70 cm deep now. In the mid-pack, a crust weakness buried in mid-December seems to be unreactive for the time being. Near the base of the snowpack is the crust-facet combination buried in November that could remain problematic, especially in shallower snowpack areas with heavy loading and warming.

Avalanche Problems

Storm Slabs

Continued snowfall, warming and extreme winds will add to the destructive potential of a developing storm slab. Storm loading may also trigger persistent weaknesses deeper in the snowpack.
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: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Wet Slabs

Watch for destructive wet slab avalanches at lower elevations where precipitation has fallen as rain, especially in areas where saturated snow overlies crusts or other weak layers. Loose wet avalanche are also a concern in steep terrain.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4

Deep Persistent Slabs

Heavy loading from snow and/or rain could trigger deep persistent weaknesses and produce isolated very large avalanches.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 6