Avalanche forecast

Avalanche forecast

Payette Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

10-18" of recent snowfall along with S/SW winds have created sensitive slabs above 7000 feet. Wind slab avalanches 1-2' thick will become likely today, especially on N, NE, and E-facing slopes near ridgelines. Rain at lower elevations will create wet loose avalanches below 7000' on slopes steeper than 35 degrees. 

Expect the avalanche danger to rise throughout the day and into the evening as another 10-18" of snowfall and strong south winds are forecasted.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    10-18" of snow has fallen since yesterday morning at upper elevations. Yesterday, moderate to strong south winds were drifting and blowing snow above 7000 feet. Today, you can expect to find dense wind slabs 1-2' thick on all aspects above 7000 feet. You are most likely to encounter wind slabs above 7500' on N, NE, and E-facing slopes. 

    You can manage this avalanche problem by avoiding wind-loaded slopes steeper than 30 degrees above 7000', particularly north through east-facing slopes just below ridgelines. Look for signs of wind-drifted snow like pillows, dunes, or large drifts. Avoid steep slopes where these signs are evident.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    The mountains in our region have received 10-18" of snowfall within the past 36 hours. Another 10-18" is expected by tomorrow morning. With the warm temperatures, the storm snow is falling as dense, heavy snow. As snowfall stacks up today, you can expect to see instabilities within the recent storm snow. These storm slabs could become sensitive throughout the day and will be most reactive later this afternoon. You can expect to see soft slabs of storm snow on all aspects below 7500'. The closer you get to 6000', this avalanche problem will transition to wet loose snow. 

    Pay attention to signs of instability like shooting cracks, whumpfing, or recent avalanche activity. If the experience these red flags, then choose a slope under 30 degrees and away from slopes steeper than 30 degrees.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–1.5

    Rain has been steadily falling on the snowpack below 6000 feet since yesterday morning. During the day, the rain level rose close to 6500' and in the evening the level dropped back down close to 5000'. The upper 4-8" of the snowpack below 7000 feet has become saturated. Yesterday, in the West Mountain zone, we saw pinwheels and rollerballs forming before noon. Expect to encounter small (less than size D2) wet loose avalanches on all aspects below 7000 feet today. 

    You can manage this problem by avoiding slopes steeper than 35 degrees in the lower elevations. Wet, loose snow releases can start slow, and small, but they have a tendency to gather speed and more dense snow as they move down the slope. Give steep slopes a wide berth today below 7000 feet.

    (3/13/2023)

    Rain on snow below 5500' created wet loose slides on Monday

    Photo: Studley

Avalanche Discussion

Today's avalanche forecast is sponsored by Franklin Building Supply of McCall. Thanks for supporting the Payette Avalanche Center.

Wet and Wild is how I would categorize this ongoing weather event. Yet another atmospheric river is pumping moisture into Idaho, bringing tropical moisture and warm temperatures. With over a foot of snow within the past 36 hours (nearly 2" SWE), we've added a heavy load onto our snowpack. Some mountain locations may receive another 12-18" (1.5-2" SWE) by tomorrow morning. Remember folks, the snowpack does not like sudden changes! The weather in the mountains was particularly nasty yesterday and is forecasted to continue today through tonight. Today might be a good day to do something else: bake some bread, tune your skis, or replace an A-arm. It's a good time to give the mountains some time to adjust to this ongoing load of snow and rain. 

Expect precipitation rates and wind speeds to intensify later this afternoon and into the evening as this low-pressure system moves across our region. The avalanche danger will rise throughout the day and into the evening hours. The destructive size of the above-mentioned avalanche problems will increase throughout the day. Avoiding avalanche terrain would be a pertinent discussion I would have with my travel partners today.