Lawinenlagebericht

Lawinenlagebericht

Payette Avalanche Center
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Lawinengefahr

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

Kernpunkte

You are likely to trigger a storm slab avalanche one or more feet thick across all aspects and elevations. Storm slabs will be most reactive above 7000' where the new snow is deeper and wind-affected. Pay attention to obvious signs of instability like shooting cracks. Avoid slopes steeper than 30 degrees if you're seeing signs of unstable storm slabs.

Lawinenprobleme

  • Storm Slabs

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

    Wet, heavy snowfall on Friday created an upside down character to the new storm snow (strong over weak). Yesterday, wet, heavy snow was failing 8-12" deep on softer snow from earlier this week. Additional snowfall last night increased the size of these storm slabs up to 10-16" thick. Storm slabs will be widespread across all elevations and aspects. Storm slabs will be most reactive above yesterday's rain line (around 7500') where temperatures stayed colder, more snow fell, and winds have drifted new snow.

    Pay attention to signs of instability like shooting cracks from your skis, board, or sled. Yesterday, I observed cracking in the new snow while breaking trail on my skis. This storm slab problem should be in-your-face and easy to find today. If you're seeing signs of instability it's time to dial back your terrain selection to slopes less than 30 degrees.

    (1/3/2025) Photo: Kevin Studley

  • Loose Wet

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

    There is a bit more uncertainty around wet loose avalanches today. Yesterday, was a no-brainer. Rain on snow up to 7400' created small natural, wet loose avalanches. Last night a cold front moved through and began dropping the rain/snow level. Precipitation likely began as rain again last night before changing to snow. What we don't know is what elevation did it start raining again last night and how quickly is the wet snow beginning to freeze. Wet loose avalanches will be most likely below 7000' across all aspects, particularly Saturday morning. 

    Don't let your guard down. Just because wet loose avalanches might be small, they could knock you off your feet and send you into terrain you didn't intend to enter. Pay attention to natural activity and dig down into the new snow to see how wet recent snowfall is.

    (1/3/2025)

    Natural wet loose activity observed around 7000' from wet snow shedding off trees

    Photo: Kevin Studley

Avalanche Discussion

Yet another warm, stormy weekend for the West Central Mountains. Cooler, seasonal temperatures this past week brought 4-6" of light snowfall with light SW winds. From December 21-29, the region saw 3.5-4.5" SWE (24-36" of snowfall) with above average temperatures. Snow changed over to rain early Friday morning and rain levels shot up to 7400'. The mountains have seen 4-8" of snowfall over the past 48 hours, with higher amounts above 8000'. Liquid totals from the past 48 hours are between 1-2" SWE. S/SW winds ramped up Friday during the day and began shifting to the W/NW. Winds will revert back to SW later Saturday afternoon but also begin to subside. Light snowfall is expected to continue through early next week as two different systems move through the area Sunday and Monday.

Triggering a deeper, persistent slab avalanche on older, weaker snow from mid-December is unlikely. We have not seen the potential for persistent weak layers (PWL) to propagate in over 10 days. The last significant loading event caused a natural avalanche cycle that was isolated to wind slabs in steep, wind-loaded terrain that did not impact these deeper PWLs. These weak layers are buried deeply (3+ feet) under a dense slab of snow and have shown signs of healing over the past two weeks.

Start the new year off right by submitting an observation on our website. Observations (i.e. YOU) can help improve avalanche forecasts. View recent observations here. Submit an observation after a day in the mountains. Tell us what you saw or what you expected to see and didn't.