Lawinenlagebericht

Lawinenlagebericht

Payette Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Persistent slab avalanches 2 feet deep are possible across all aspects and elevations. These avalanches could step down to older, weak snow near the ground creating a very large avalanche (D2-D3). Recent warm temperatures and rain have made wet loose avalanches possible below 7500'.

Lawinenprobleme

  • Deep Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    2–3

    Triggering an avalanche on deep persistent weak layers from November is unlikely. The poor snowpack structure continues to raise alarm, especially with continued weight being added to the snowpack. Warm temperatures and rain/snow are adding weight to the slab and stressing buried weak layers. You are most likely to trigger a large avalanche within old snow near the ground in steep, rocky terrain where the snowpack is shallow. You're not likely to see or hear any signs of instability on this weak layer buried over 3 feet deep. Although, if you dig into the snowpack, you'll most likely find evidence of it. The biggest concern with this deep persistent slab is triggering a persistent slab within the upper snowpack and stepping down deeper to weak snow near the ground. These avalanches would be large enough to destroy a small house, such as the one that occurred naturally earlier this week in Deer Creek.

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–2.5

    2-4 feet of new snow last week fell on a variety of buried weak layers. This recent snow formed a slab about 2 feet thick overlying persistent weak layers that were buried in early January. Between solar and shaded aspects, you'll find a layer of buried surface hoar/near surface facets OR facets sandwiched between two melt freeze crusts. Both of these weak layers are about 2 feet down and are slowly strengthening. Unfortunately, this persistent slab problem is widespread across all aspects and elevations. The photo of an avalanche to the right highlights this persistent slab problem. This avalanche propagated across NE, E, and SE aspects. Even on NE slopes, the weak layer was facets between two melt freeze crusts. Avoidance of slopes steeper than 30 degrees is the only sure way to manage this persistent slab problem.

    (1/19/2024) Looking up at the start zone from the Anderson Creek road Photo: Kevin Studley

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Yesterday, temperatures were in the mid 30s at upper elevations. The snow surface was moist up to 7500' yesterday. Water was pouring off trees throughout the afternoon hours. Last night, rain levels increased to around 7000'. Small wet loose avalanches are possible today on all aspects below 7500'. Below 7000', the snow surface will be more saturated and unstable within the upper several inches of the snowpack. Avoiding lower elevation slopes steeper than 35 degrees would be a good idea today. Even a small wet loose avalanche could step down to a persistent slab avalanche (problem #1).

Avalanche Discussion

Yesterday, we visited the site or a large avalanche that was reported in the Deer Creek avalanche path on West Mountain. You can read my observation here. Another observation was submitted yesterday from a local snowmobiler about an avalanche near Lone Tree south of Tamarack Resort. It's safe to say the zone in and around West Mountain is currently more reactive than other areas within our forecast zone. Two persistent slab problems and a recent warmup/rain on snow event, today is not the day to charge for the steep slopes. The warmup yesterday and today will add more stress to buried weak layers in the snowpack. Complicating things further is the fact that rain fell up to around 7000'. If you're traveling in the backcountry this weekend, the discussion you should be having with your partners is about multiple avalanche problems and how you're going to avoid them.

Get your name in the hat to win some gear in our FPAC monthly drawing when you submit an observation. Submitting an observation improves your skills, informs other users, and benefits avalanche forecasts. Simple photos highlighting conditions are very helpful.

Did you know there several avalanche classes this month specifically for motorized users? Check out our classes and events page to learn more.