Lawinenlagebericht

Stevens Pass

Feb 22 – 23, 2015Northwest Avalanche Center
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Archiviert · abgelaufen 12 years ago

Lawinengefahr

Tue
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering

Kernpunkte

Small loose wet avalanches and lingering wind slab will most likely be found above treeline Monday. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    1
  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1

Detailed Forecast

Generally light winds and warmer temperatures are expected Monday as freezing levels rise to 8000-9000 feet. 

As a result, small loose wet avalanches involving the most recent storm snow should be possible on steeper solar slopes near and above treeline in the late morning or early afternoon. 

Recent shallow wind slab formed on non-traditional westerly aspects above treeline may still be sensitive. 

Due to the low snowpack, especially below treeline, watch for terrain hazards such as open creeks, partially covered rocks and vegetation. Many areas below treeline do not have enough snow (new or existing) to pose an avalanche hazard. 

Snowpack Discussion

Since the warm and wet start to February, fair weather through mid-February has lead to generally thick surface crusts and further consolidation of the snowpack, as well as further deterioration of the snow cover below treeline.

A few weather disturbances passed through the latter half of the week, bringing a welcome few inches of snow near and above treeline. Winds veered to the east or northeast on Saturday, causing some new wind slab formation on non-traditional westerly aspects mainly above treeline.  

On Saturday, NWAC observer reports from the Crystal Mt backcountry described a few inches of new snow bonding well to the old surface through mid-day. However, at Winchester Mt in the Mt. Baker area, new wind slab 10-40 cm thick was observed above treeline on multiple aspects with new NE wind transport in progress. A small loose wet slide was triggered on a south slope late in the day even with the the cold temperatures and wind. On Sunday, Dallas Glass at Skyline found the 10-15 cm of most recent snow well bonded near treeline with minimal new wind transport.  

The mid and lower snowpack west of the crest snow consists of layers of stable consolidated rounded grains or melt forms and crusts from multiple warm periods this winter.

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