Bollettino valanghe

Northern New Mexico

Taos Avalanche Center
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Pericolo valanghe

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

In sintesi

The current storm pulse could add up to a foot of new snow and 0.8" SWE over the next 24 hours in areas throughout the Northern Sangre de Cristo Mountains. Heavy snowfall plus winds at upper elevations will lead to increasingly reactive storm slabs, and those slabs are likely not bonding well to the hard slabs and crusts underneath. Dry loose avalanches are also a concern in wind-sheltered areas. Triggering a smaller avalanche on the surface has the potential to step down into deeper weak layers. Faceted crusts and buried near surface facets from February and early March are widespread and found in the upper portions of the snowpack. These avalanches could break widely across the slope and may break well above you. Deeper down in the snowpack, facets and depth hoar continue to linger in shallow snowpacks and would produce a large avalanche that could take with it most of the season's snowpack. Cautious route planning and conservative decision making will be essential today with this confluence of avalanche problems. Your safest option is to stick to low-angle terrain situated far away from avalanche paths.

Problemi valanghivi

  • Storm Slabs

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

    We've seen a wide range of snow (4-10") across our forecast area over the first few days of this storm. Today's snowfall is expected to be the strongest so far, so expect these numbers to double in some places over the course of the day. Storm slabs will continue to build today, especially with the East wind blowing strongly enough to transport that new snow. These storm slabs are sitting on top of a variety of different surfaces, from firm hard crusts on solar aspects to wind-pressed surfaces above treeline and near-surface facets on shady northerly wind-sheltered slopes. Storm slab avalanches may fail on the old snow/new snow interface or within the storm snow on density changes or graupel layers. With easterly winds expect to find loading in atypical places at upper elevations. Watch for shooting cracks on the surface, avoiding obvious wind-drifted pillows or stiffening of snow underfoot. A smaller avalanche within the new storm snow has the potential to step down into deeper weak layers, creating a larger and more destructive avalanche.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–2.5

    Buried near surface facets and faceted crusts from the end of the February and early March dry periods are buried up to 2 feet below the surface and continue to remain fragile and weak. These weak layers have seen incremental loading over the last several days and that could double over the course of today's snowfall.  These newly formed slabs should make avalanches that fail on these weak layers more likely.  Deeper down, facets and depth hoar continue to remain present in shallow (< 1.5m)  snowpacks. With each significant storm this year, we've seen these layers become more reactive and produce avalanches. Pay attention to obvious signs of instability like shooting cracks and loud audible collapses. It's possible to remotely trigger an avalanche or have an avalanche break well above you in these conditions.

    East Aspect near treeline. Near-surface facets about 35-40cm deep failed on easy force in this spot. The current storm pulse may make these layers increasingly sensitive to human triggers.

    Photo: Charlie Harrison (3/14/2024)

Avalanche Discussion

It's been a low-output storm for us so far, but that all changes today as the cutoff low centered over Arizona pushes at bit more East. The heaviest snowfall will occur at upper elevations in our range, with up to a foot forecasted over the next 24 hours. That being said, I expect the snow totals to be highly variable across our forecast area due to the nature of this storm. Don't be surprised if the snowfall changes significantly over the course of a mile or 1000 ft of elevation gain. It'll be a great day to head out and get your March powder turns in, but you also need to be vigilant about the heightened risk of avalanches.

New snow concerns will be the most obvious avalanche problem and we expect to see more reactive storm slabs near and above treeline today, where moderate winds are drifting snow into stiffer, more cohesive slabs. These slabs may fail at the old snow interface on slick smooth crusts on solar aspects or near-surface facets on wind-sheltered northerly aspects. Expect to find these wind-drifted slabs in unusual places today with the East winds. These avalanches will be relatively small but could step down into weak layers in the top 1 to 2 feet of the snowpack. In wind-sheltered terrain, expect to find loose snow that slides around easily, especially if it sits on top of a crust. Loose snow avalanches releases will be the primary concern below treeline and in wind-sheltered areas that receive plenty of snow today.

The main persistent weak layers of concern are buried near surface facets and faceted crusts in the upper portions of the snowpack that formed during the dry periods at the middle to end of February and early March. These layers are widespread across most aspects and all elevations. These weak layers have been producing easy results in extended column tests with planar failures. We haven't seen much cracking and collapsing in our travels, but with rapid loading and slab development likely today, these warning signs should become more present. Even if you don't observe cracking and collapsing, take the time to dig a pit and identify if these weak layers are present. We've seen slow, incremental loading during this storm so far, but the current pulse could double that load today in many places making it easier for you to tip the scales and trigger a larger persistent slab avalanche.

Deeper down in the snowpack, the early January drought facet layer and depth hoar near the ground continue to remain present in shallow snowpacks but have been lying dormant as we haven't seen a significant loading event in over a month. These layers could become more reactive with the aforementioned loading and slab formation of the current storm pulse. For this kind of avalanche, I'm the most suspect of our shallow, steep terrain, such as avalanche paths that already slid this year. Stay far away from that kind of terrain today. Additionally, I'll point out that any persistent slab avalanche that fails in the upper meter of snowpack is an excellent trigger for these kinds of deeper persistent slab avalanches. This confluence of issues is more than enough to keep me off of high consequence avalanche terrain today.

If you go hunting for buttery pow turns today, don't try to be a hero and remember the reality of our weak snowpack. With the current setup, it's in your best interest to just ditch skiing avalanche terrain altogether and go find some stress-free low angle powder or ride inbounds. But if you decide to venture outside of that box today, evaluate the snowpack where you plan to ride really carefully and use extreme caution in your terrain management techniques. Be ready to bail out and resort to a lower-consequence option at the first sign of instability, or if you find a slab overlying any of the weak layers I just mentioned. Happy March turns, and please be safe out there!

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