Avalanche forecast

Avalanche forecast

Payette Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

Triggering a persistent slab avalanche 2+ feet thick is becoming unlikely, although not impossible. You're most likely to encounter this persistent slab problem on slopes that have weak snow in between melt-freeze crusts from late March. Wet loose avalanches will increase today as temperatures warm and solar radiation increases. Pay attention to wet snow shedding off steep rocky areas that face the sun. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1.5–2.5

    A persistent, weak layer of facets above melt-freeze crusts from late March is buried about 75-90 cm (2.5-3 feet) below the surface. This crust/facet sandwich has been consistently observed on east through west aspects on the southern side of the compass. On NW, N, and NE-facing slopes, the crust/facet combination is not as pronounced, but a similar structure is present with weak layers or weak interfaces 2-3 feet down. Last weekend's storm dropped 1-2 feet of snow on these weak layers and a lot of steep terrain avalanched naturally. The likelihood of triggering a large, persistent slab avalanche has decreased. However, the consequences of triggering a large, destructive avalanche remain unchanged.

    It will be easier to impact these buried weak layers with the weight of a machine as opposed to the weight of a person. Steep slopes that are holding this crust/facet combination should be approached cautiously. Look for shallow spots in the snowpack (thin, rocky areas) and avoid these places as they can act as the perfect spot to trigger an avalanche.

    ADDITIONAL DISCUSSION: Watch for isolated pockets of wind slabs today. Strong SW/W winds accompanied the weekend storm and shifted out of the north Monday and Tuesday. Pay attention to clues that indicate wind slabs may be present in terrain above 7500', such as recent drifts, pillows, dunes, or cornice formation. Avoid steep areas where wind slabs are suspected.

  • Loose Wet

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

    Yesterday, was the second clear day since last weekend's storm. Between the clouds and cooler air temperatures, wet loose avalanches have been fairly limited the past two days. Today will be another clear day and warmer than yesterday. I expect snow to be shedding off steep rocky areas today. Watch out for wet loose avalanches on south-facing slopes as temperatures increase toward mid-day and snow becomes moist. Wet loose avalanches up to one foot deep will be possible on steep terrain that faces the sun. Plan your outing accordingly, as east-facing slopes will warm first, following the sun through the sky to SE, S, SW, and then W slopes by early to late afternoon.

    Pay attention to moisture in the upper snowpack. Are you sinking past your boots? Is your track punching into soft, wet snow? If so, then it's time to find another slope that is not catching as much sun. Watch out for steep, rocky terrain above you. This type of terrain is perfect for creating wet loose avalanches. 

Avalanche Discussion

Today's avalanche forecast is sponsored by Brundage Mountain Resort. Thanks for supporting the Payette Avalanche Center.

The avalanche danger peaked last weekend during and just after the intense winter storm. SNOTEL sites have recorded up to 6 inches of settlement over the past three days. Stability is improving, but the slight possibility of triggering a persistent slab avalanche should be part of your discussion today with your travel partners. An important point to take away from today's forecast is that even though the calendar reads April 6th, WE DO NOT HAVE A SPRING-TIME SNOWPACK YET. Typically this time of year, it can be warm and sunny in the mountains and we're in a diurnal, melt-freeze cycle. That has not been the case this spring. We have a very deep and winter-like snowpack that still has persistent weak layers. Even though the weather will be feeling like spring today, the snowpack does not reflect this feeling. Two to three days of clear, sunny days are not enough to instantly change a winter snowpack to a spring, isothermal snowpack. It is not open season out there folks. Your terrain selection should reflect the avalanche problems, not the weather.

Don’t miss out on the End of the Season update and State of the Snowpack this Friday, April 7 at 5 pm at Toll Station Pizza and Pasta. The PAC will issue its last avalanche forecast on April 8 but there is still a lot of good riding and sliding to be done in our local mountains. Come out and support the FPAC and get an update on what is happening in the snowpack and what you should be thinking about through the rest of the spring season.  You can also meet the new FPAC Board members and find out how you can get involved or help us support the PAC. The cost is $20 at the door and covers food and beverages as well as a donation to the FPAC to help support the PAC.     Thanks to all of those people who’ve submitted observations this season. We’ve randomly selected two winners (motorized and human-powered) from each month to receive a prize for their observation. The winners thus far are:   December: Sam Thackeray and Jerome Sawyer Kovis January: HP Marshall and Dimitry D February: Jamie Shaw and Austin Wrem   There’s still time to submit an observation to be entered into the final end-of-season drawing. Don’t miss out!