Lawinenlagebericht

East Slopes South

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

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

Kernpunkte

Snowfall and extreme winds will rapidly increase avalanche danger by Monday morning. New and wind drifted snow may bond poorly to slick old snow surfaces, and avalanches could break widely across terrain features. Give the snowpack time to adjust and avoid steep wind-loaded slopes at upper elevations.

Lawinenprobleme

  • Wind Slabs

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

    The storm will start out warm and wet and finish cold with the heaviest precipitation expected Sunday night. Snow levels will start near 4500ft and lower to 1000ft by Monday morning. Strong to extreme westerly winds will blow, and new snow will be redistributed into reactive slabs in leeward terrain. You may encounter unstable wind drifted snow in many areas, but the most dangerous will be east-facing slopes 35 degrees and steeper near and above treeline. In these areas, large avalanches will be easy to trigger, and a few could even run naturally over the next 24 hours. 

    Ease into terrain slowly and choose simple slopes away from the runout of large avalanche paths. Carefully assess how new snow bonds to firm, icy old snow surfaces and watch for sudden and easy failures in snowpack tests. Recent avalanches, cracking, and collapsing should direct you to low-angle terrain sheltered from the wind. 

    (Example Photo) Windy conditions during the storm Sunday night will form fresh cornices and load slopes near ridgelines. Avalanches in wind drifted snow will be likely on slopes below.

    Photo: Dallas Glass

Avalanche Discussion

A fast-moving winter storm will finally bring an end to the prolonged period of dry, sunny weather. Thick, firm crusts are widespread across all aspects and elevations, and new snow may not bond well initially. This new/old snow interface will be the focus of avalanche concerns moving forward. It is certainly slick and icy and will be a good bed surface for avalanches. It may even harbor weak snow in some high elevation terrain that stayed cold and shady in recent days. A wet and windy start to the storm may rule out these concerns. We will have to see how it all plays out, so gather information as you travel and build in a wide margin for error. The old snow surface will be easy to find. Be sure to carefully evaluate how new snow bonds, and be patient in the coming days as the snowpack adjusts to this rapid change.

Over the past three weeks, conditions were unseasonably warm and the snowpack endured a beating. There was a significant loss in overall snow height, and many ridgelines, south aspects, and low elevation slopes melted out to bare ground. Several creeks also reopened during the warm weather and many snow bridges fractured or collapsed. Shallowly buried obstacles will be an additional hazard to deal with in the coming days hidden beneath the new snow. 

Abgedeckte Regionen