Bulletin d’avalanche

Bulletin d’avalanche

Payette Avalanche Center
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Danger d’avalanche

Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Use caution on all slopes steeper than 30 degrees: Human trigged as well as natural Loose snow avalanches are possible on steep slopes within the upper 1-2 feet of the snowpack. Winds Tuesday have created slabs 6-10" deep in leeward terrain that may still be sensitive to the weight of a person. Signs of wind activity may be hidden underneath recent new snow. 

Problèmes avalancheux

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    Slopes steeper than 35 degrees are going to have the ability to produce Human and Natural Triggered loose dry avalanches, and or sluffs within the upper 1-2 feet of the snowpack. The snow can move with you and has the potential to build up deep and push you into terrain traps like gullies and over cliffs and rocks. Planning your lines, or sluff management is going to be a necessity as the more exposed and sustained a slope is.

    The upper foot of the snowpack was unconsolidated and very cold and dry yesterday in our travels near Lick Cr Summit East of McCall.  Aspects that tilt towards the sun also lacked cohesion in the upper foot, but shady aspects are going to be deeper. With more new snow overnight and a little more forecasted today (More in the Southern portion of our advisory area), we will likely see this problem grow in size today.

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Winds early Tuesday morning gusted in the 20 mph range mostly out of the Southwest and created wind slabs in leeward terrain which was mostly E and NE, but cross-loading on other W, SW & NW aspects were observed yesterday throughout the Lick Cr drainage, so use caution on all aspects in upper elevation terrain, especially near ridgelines and cornices. If you are seeing red flags like cracking turn around and find another route.

    On Tuesday we got a couple of observations of wind slabs. One from Tamarack on the ridge where a skier had triggered a cornice, and an observation from Lick Cr: Found wind slabs 6-10" thick in upper elevation leeward terrain. 10-15 cm of fresh snow sitting on top of 20230220 rime crust at 7000 feet, East North East aspect.

    (2/21/2023)

    Observation submitted to our Observation page from just North of Tamarack Ski Area on West Mountain:

    Skier Triggered East facing slope. 3 foot crown which slid almost 50 feet and around 25 feet wide. Large crack beneath crown.

    Photo: Public

Avalanche Discussion

Today's Advisory is sponsored by Brundage Mountain Resort. Thank You for supporting the PAC!

Our test pits have shown a snowpack that is unconsolidated in the upper foot and strong enough to not propagate fractures.  The more South that a slope faces will also determine how thick of a sun crust that is buried beneth the new snow and has not been showing signs of bonding to the new snow beneath it as it has faceted---this will not hold up with more and more snowload.

While you are having fun today in the fresh powder, watch your partners from a safe location on slopes that are steep enough to slide (^30 degrees), and make sure you are using good basic travel protocols like only one person on a slope at a time and wearing a transiver, shovel, and probe on your person. With more snow, today along with more wind forecasted tonight the loose snow and wind slab avalanche problems will grow.