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 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Dangerous avalanche conditions will continue into Saturday.  Start your day in simple terrain. Limit your exposure to slopes steep enough to avalanche until the new snow has time to settle. Be on the lookout for barely filled-in creek holes and other obstacles uncovered with heavy rain last weekend.

Lawinenprobleme

  • Storm Slabs

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

    Another 8-12” of snowfall overnight means the types of new snow avalanches observed today could happen again tomorrow. There may be fewer natural avalanches but the general setup is the same - heavy snowfall into the morning with winds strong enough to transport snow. You are more likely to trigger avalanches on slopes with recent wind loading but consider all steep terrain as suspect until proven otherwise. A cooling trend with the end of the storm might make for less volatile conditions. 

    Keep an eye on new snow and wind slab layers using simple tests - hand shears, test slopes, skin track tests, etc - and adjust your plan based on what you see. The easier the new snow slides on the layer below, the more likely it is you will trigger an avalanche in steep terrain. Shooting cracks and recent natural or human triggered avalanches are explicit signs of continued instability. Heavy, wet snow at lower elevations could make for challenging travel and also produce rollerballs or even small loose wet avalanches.

    (12/30/2022)

    Crown of a slab avalanche that released within new snow layers. A south aspect on Herman at ~4700'.

    Photo: Kameron Decker Harris

Avalanche Discussion

Numerous natural and human triggered avalanches to D2 were reported with Friday's storm. Avalanche mitigation work the same morning produced many small and shallow avalanches that released within new snow layers. A few larger avalanches occurred in wind loaded terrain. Up to 16” of new snow falling during a subtle warming trend was accompanied by strong winds. The result was slabs that were very reactive and had wide propagation. Some were triggered from below. Stormy conditions and snowfall persisted throughout the day. Rollerballs and the occasional small, wet loose avalanches were reported with warming at low elevations.

The pattern of avalanche activity Friday shows how volatile conditions can become in a short period of time. It also highlights the necessity of making and acting on your own observations.

The 8-14” of rain from December 23rd through the 27th reshaped the winter landscape at and below the snow surface. The existing snowpack was basically reset as a deep layer of wet grains now topped by snow from recent storms. Large creek holes and other oddly shaped terrain features opened up with the rain. Rocks and other objects melted out and were then barely covered with new snow. Use caution in poor visibility and when entering rollovers and other undulating features. It’s going to take more than a few storms to fill in some of the bigger holes that formed during the rain event.

Abgedeckte Regionen