Bollettino valanghe

Northern New Mexico

Taos Avalanche Center
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Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

New snow and strong winds will create dangerous avalanche conditions near and above treeline today.  Freshly formed slabs that could grow to 1 to 2 feet thick will rest on top of a shallow weak faceted snowpack. Avoid being on or connected to terrain over 30 degrees, paying attention to obvious signs of instability like loud audible collapses and shooting cracks.  Any avalanche triggered could break widely across the slope and terrain features, taking with it most of the season's snowpack. 

Problemi valanghivi

  • Persistent Slabs

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

    New snow and wind will create dangerous avalanche conditions near and above treeline where freshly formed slabs rest on top of very weak faceted snow.  The rapid load and weight of new snow will greatly stress these persistent weak layers near the ground. Warning signs like loud audible collapses and shooting cracks are indications that you've found unstable snow.  These types of conditions lend themselves to remotely triggering an avalanche from the flats or a distance away.  Avoid being on or connected to steep slopes above you. Any avalanche triggered could be large enough to injure or bury you, and most likely will take with it most of the season's snowpack. 

    An example of a shooting crack, this is an indication you've found a poor snowpack structure of strong cohesive snow over weak faceted snow.  

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Moderate to strong S/SW winds at ridgetops will drift new snow into cohesive wind slabs at upper elevations.  Watch for firmer snow underfoot or pillowed-like features below ridgelines and in cross-loaded terrain features. Although you may be able to trigger a wind slab that runs in the new snow or on the old snow interface there's a good chance it will step down into deeper older weak layers creating a larger and more dangerous avalanche. 

Avalanche Discussion

Heavy wet snow started falling at 3 AM with snow levels around 8000' and has quickly deposited 4 inches of snow by 5:30 AM.  S/SW winds are in the  15 - 35 mph range gusting in the 60's.  Snowfall is expected to continue throughout the morning with a brief lull mid-day before more snow showers pick up this afternoon through the evening. Snow levels are expected to remain around 8000' through mid-day before dropping in the afternoon as the second pulse of moisture moves through.  

 Before this storm, we've had a week of high pressure that has felt spring-like with warm sunny days and colder clear nights.  Our snowpack that has been shallow (30 - 75 cm) has continued to facet and on most slopes consists of facets and depth hoar from top to bottom. Solar aspects have formed crusts on the surface with weak snow underneath.  The snowpack overall is shallow and weak, with ski and boot penetration going all the way to the ground in most places.  South aspects have mainly melted back to bare ground. 

At upper elevations on northerly and east aspects. previous storms and wind events have created a slab/weak layer combination that has only produced small avalanches from explosive control work just after the storm from 12/15.  Signs of instability like cracking and collapsing quickly diminished as well as avalanche activity. Over the week of high pressure, slabs that formed during this storm have weakened and have been faceting over the last week of high pressure.  Widespread near-surface faceting and surface hoar were present in the upper portions of the snowpack in travels yesterday.

A shallow (40cm) Snowpack around 11,000' on a northerly aspect on 12/22  

The one constant in the snowpack right now is a widespread faceted/depth hoar weak layer.  Now that we'll be introducing a slab on many slopes, we'll have all the ingredients needed for a slab avalanche. Rapid loading from heavy snowfall and strong winds will quickly add weight and stress these persistent weak layers to where we could see some natural avalanche activity as snow totals add up.  Upper elevations will see the greatest amount of loading, but don't let your guard down below treeline, especially on northerly steep slopes that are open and exposed to the wind. 

 

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