Boletín de aludes

Northwest Mountains

Crested Butte Avalanche Center
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Peligro de aludes

Mon
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Westerly winds have combined with 3 to 6 inches of snow to create wind slabs below some ridgelines and cross-loaded terrain features. Take time to investigate this potential avalanche problem before committing to steep avalanche terrain. Normal caution is expected in areas that haven't seen any wind loading. 

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    2 to 4 inches of snow accumulated in the last 12 hours, bringing storm totals up to around 6 inches of snow for some areas. Yesterday, westerly winds averaged in the 20 to 30mph range with stronger gusts at 12,000ft. The wind direction became southwesterly overnight, while wind speeds decreased around 10mph on average. The specific locations to keep an eye out for new slab development would be on the leeward sides of ridgelines and in crossloaded gullies. Consider utilizing small test slopes to help identify the potential size and how reactive this avalanche problem is in your area. 

    An example of shooting cracks along a wind-loaded ridgeline from earlier this winter. 

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    1–2

    Old hard slabs up to several feet thick have become isolated and difficult to trigger. You are unlikely to see signs of instability before triggering an avalanche that breaks on old weak layers.  The most likely trigger poits would be where these hard slabs thin near their margins, on convexities, or near rocky areas.

    This hard slab was triggered near Pearl Pass on 2/3.  This location is just beyond the CBAC's Southeast Mountain forecast boundary. 

    Photo: CAIC

Avalanche Discussion

Powder day number 2! Yes, our standards for a powder day have become very low. The Gunnison River Basin has dropped to 80% of the median. So, any amount of new snow is much needed and will be celebrated! 24-hour snow totals are around 6" in the NW Mountains, with .5 SWE having been recorded at Schofield Pass. Storm totals at Irwin were 4.5" with .4 SWE as of about 4pm yesterday. Irwin likely received an additional 1 to 3 inches of snow overnight, though remote weather stations in the area didn't produce consistent readings during that time. The SE Mountain forecast area, of course, recorded less snow in the last 24 hours and appears to be in the 1 to 3-inch range. There may be more snow in the higher data sparse areas like around the Friends Hut for example.   

The snowpack has gained stability with recent cold temperatures following a wet avalanche cycle and a period of above-average temperatures early this week. With continued cold temperatures in the forecast, our focus has shifted to new avalanche problems. The new avalanche problem is wind slabs. There isn't a ton of snow to blow around, so slab development is expected to be on the smaller end of the scale.  With transportable winds in the forecast tonight, the danger trend was left steady. The danger trend may drop once there is higher confidence in the size and distribution of these new slabs. 

The old Persistent Slab problem is unlikely due to an isolated nature across the landscape and a difficult-to-trigger sensitivity.  You can find old, hard slabs of snow below ridge tops, cross-loaded in gullies, and pressed into concave features. A few slabs released during the warmup at the start of the week. Otherwise, the only other recent activity releasing into old snow was this skier-triggered hard slab just outside the CBAC forecast boundary near Pearl Pass on 2/3. 

For more on last week's weather and avalanche events, check out the weekly summary here. 

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