Bollettino valanghe

Gunnison

Crested Butte Avalanche Center
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Pericolo valanghe

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

In sintesi

New snow has combined with southwest winds to form new wind slabs on the lee sides of ridgelines and cross-loaded terrain featuers. You'll need to assess the size and sensitivity of this avalanche problem before committing to steep wind-loaded terrain or consider traveling around those terrain features. On northerly facing slopes there remains a low probably to human trigger a large slab avalanche that fails on deeper persistent weak layers. The most concerning areas for this persistent slab avalanche problem are where the total snowpack is variable in depth due to rocky outcrops or previous wind effects. Normal caution is expected at lower elevations, with the potential for loose snow avalanches in steep terrain, or isolated areas with small wind slabs. 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    In the last two weeks, the majority of slab avalanche activity has occurred on a layer of facets that was buried on 3/23. The last persistent slab avalanche was human-triggered on 5/3. The late March interface is now buried 2 to 5 feet deep and is gaining strength. Future avalanche concerns are transitioning away from this specific interface, and back to more isolated areas that have a weaker-than-average snowpack. Areas with a relatively shallow snowpack will have more pronounced layers of facets that have developed throughout the winter. The most common areas to find these weaker snowpacks will be steep rocky slopes with variable snowpack depths, and areas where previous winds have eroded the total snowpack depth creating large fluctuations in that snowpack depth across the terrain. This video sums up an example of this type of terrain. 

    Avalanche crowns spanning steep, rocky terrain. This avalanche ran sometime during last weekend's storm. 

  • Wind Slabs

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

    Overnight, remote weather stations between 11,000 and 12,000ft recorded moderate to strong winds from the south to southwest on average. These winds have formed wind slabs on the lee sides of ridgelines and cross-loaded terrain featuers. Those slabs have formed over crusts and potentially small facets on northerly-facing slopes. Most of these slabs will be small in size, while some potential wind slabs could produce large avalanches in the alpine or a few areas with a notably big fetch. Wind Slabs can be avoided by sticking to sheltered or wind-scoured areas.

    An example of a small wind slab that failed below a wind-loaded ridgeline earlier this winter. 

Avalanche Discussion

Here are the 5AM snow numbers for last night. Schofield Pass: 5" with .3 SWE. Lake Irwin: 5" with .3 SWE. Elkton: 5". CBMR Pow Cam: 3". There is some additional snow in the forecast that will hopefully keep increasing these numbers today. 

Overnight, remote weather stations between 11,000 and 12,000ft recorded moderate to strong winds from the south to southwest on average. The strongest wind gusts were in the 30 to 50mph range since midnight. 

This morning we have transitioned back to winter, after a week of hot weather and wet avalanche activity. A wind slab avalanche problem was added this morning, and this avalanche problem will continue through the weekend. The distribution of the persistent slab avalanche problem was changed yesterday to remove areas that now have thick crusts or water having drained deeply into the snowpack after last week's warmup. We are also starting to transition the weak layer of concern from the March 23rd interface, back to areas holding a variety of potential weak layers due to a weaker-than-average depth on steep rocky slopes or from previous wind effects. 

 

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