Bollettino valanghe

Bollettino valanghe

Payette Avalanche Center
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Pericolo valanghe

Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

This morning's avalanche danger will be LOW. 4-8" of snowfall today will increase the avalanche danger throughout the day and into the evening. New snow will not bond well to previous snow surfaces such as melt-freeze crusts. Expect dry loose avalanches to increase in size and likelihood throughout the day.

Problemi valanghivi

  • Loose Dry

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    4-8" of snowfall is expected throughout the day and into the afternoon hours. On northern aspects, the upper foot of the snowpack is comprised of 4-8" of softer snow sitting atop denser snow. On east through west aspects on the southern side of the compass, this softer snow is sitting atop a melt-freeze crust that was buried on Monday. Weak, faceted snow has been forming above and below this crust. Southern aspects will also be holding a melt-freeze crust that formed from the past two days of warm, sunny weather. All of this will be getting buried today.

    So what? The primary avalanche problems today will be new snow problems. Expect new storm snow to bond poorly to previous surfaces and move easily on terrain steeper than 35 degrees. For most of the day, I expect dry loose (or sluff) to be the primary concern on all aspects and elevations. Loose snow avalanches will be the largest and therefore most destructive on NW, N, and NE-facing slopes above 7000'. On other aspects and lower elevations, I expect dry loose avalanches to be smaller. However, new snow will not bond well to slick surfaces (such as melt-freeze crusts), although smaller in size, dry loose avalanches on south-facing terrain will move easily on slopes steeper than 30 degrees.

    Loose snow (sluff) can be a manageable avalanche problem. But you have to know where it is, how it's changing, and how to safely manage the terrain you're traveling in. If you find yourself in terrain steeper than 35 degrees with loose snow moving, avoid terrain traps such as gullies, depressions, cliffs, or steep slopes that run into trees.

    ADDITIONAL DISCUSSION: As snowfall stacks up throughout the day, shallow storm slabs will become possible this afternoon. Storm slabs will be the most sensitive in wind-exposed terrain above 7000'.  Similar to dry loose avalanches, storm slabs will not bond well to existing snow surfaces, especially on solar aspects with a melt-freeze crust. Pay attention to changing snow conditions throughout the day. As snowfall rates increase, watch for red flags like shooting cracks or collapsing of older, weaker snow. These signs are indicators of unstable snow conditions and you should make more conservative terrain choices throughout the day.

Avalanche Discussion

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

The Miraculous March continues. The West Central Mountains are under a Winter Weather Advisory for the next 24 hours. 6-12" of snowfall is possible for mountain locations, with locally higher amounts possible. Temperatures are forecasted to drop tonight bringing unseasonably cool weather. The month of March has already provided 5-7 feet of snowfall (6+" SWE) to our region. We've received accumulating snowfall in 16 of 23 days so far this month. A large, widespread natural avalanche cycle occurred last Tuesday (14th). Since then, we've had two stretches of warm, spring-like weather. (Yes, it is March after all folks). High temperatures recorded from the Secesh SNOTEL site (6540') peaked Sunday (19th) at 43 F and Wednesday (22nd) at 44 F. Those dry stretches have left our snowpack with two separate melt-freeze crusts and lingering pockets of surface hoar. With over a foot of new snow expected through Saturday, expect avalanche problems to increase and avalanche danger to rise into the weekend.