Lawinenlagebericht

West Slopes North

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
Open full map
Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

You can trigger wind slab avalanches in the last 48 hours’ wind affected snow. It is unclear how well the snow bonded to the layers beneath it, and you may find drifting in unusual locations due to the extreme wind. Stay off wind loaded slopes steeper than 35 degrees until you’ve assessed the bond with underlying layers on small slopes.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Wind slabs developed with Friday’s snowfall and extreme winds, and we are unsure how reactive these newly loaded deposits are. The extreme winds redistributed snow into unusual areas, such as further downslope than normal, or at lower elevations. You might find them below cliff bands or in gullies.  Identify wind loaded deposits by feeling for firmer snow and noticing visual clues such as smooth pillows or textured surfaces. You may have difficulty finding the slabs because more snow may have fallen with minimal wind on top.  

    Investigate the slabs by digging quick pits down to the layer below, and determine how readily the slab slides on the underlying layer. Stick to small test slopes before even considering larger terrain. Until proven otherwise, avoid wind loaded slopes steeper than 35 degrees. 

    An example of a wind slab like you might see or trigger on Saturday Photo: Patrick Kennedy

Avalanche Discussion

By Saturday morning over 2 inches of water will have fallen at the Heather Meadows weather station. Snowline started around 4500ft but dropped to around 2000ft overnight, and it will rise a little during the day on Saturday. Well over a foot of snow fell above 5000ft. Yesterday’s wind gusts peaked at 70mph from the south midday at the Pan Dome, extensively redistributing the snow. 

There are layers of concern in our snowpack buried around 10 feet deep, although most  recent avalanches failed on shallower layers in this zone. The new snow load may test the deeply buried weakness. We last saw it about a week ago, when there was a widespread natural avalanche cycle that resulted in many very large avalanches (D3+), some hitting Highway 20 just outside Newhalem. Several very large avalanches were reported further south in the zone. Our concern, a mid January deep persistent layer is 200 - 300cm deep in most areas and is hard for a human to trigger. However, a huge sudden load such as a cornice fall could trigger an avalanche on that layer. 

Snow and avalanche conditions are variable in the West North zone and throughout the Cascades right now. In general, recent storm snow is stabilizing quickly, but very large natural avalanches along the border of the Stevens and West Central zones continue to keep these old and deep weak layers on our minds in this zone as well. Read the West Central or Stevens Pass Forecasts to learn more about it. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home

Abgedeckte Regionen