• Backcountry Avalanche Forecast
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Mon, Dec 6, 2021 at 7:09 AM
Issued by: Mike Cooperstein

Monday

 

Tuesday

Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.   Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.   Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.   Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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Summary

Most slopes don't have enough snow or lack the requisite slab for dangerous avalanches. There is a small chance you can trigger an avalanche in very steep terrain on north, northeast, and east-facing slopes in the alpine. If you are traveling in above treeline areas, look for and avoid spots where you see signs of previous wind-loading like fat pillows of snow or a smooth, hard, hollow-sounding snow surface.

 
Weather Forecast for 11,000ft Issued Mon, Dec 6, 2021 at 12:27 PM by Mike Cooperstein Statewide Weather Forecast
  Monday Night Tuesday Tuesday Night
Temperature (ºF) 16 to 21 22 to 27 14 to 19
Wind Speed (mph) 25 to 35 12 to 22 13 to 23
Wind Direction WSW WSW WSW
Sky Cover Mostly Cloudy Mostly Cloudy Mostly Clear
Snow (in) 0 to 1 0 0

Archived Forecasts

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Mon, Dec 6, 2021 at 7:52 AM
Issued by: Jeremy Yanko Statewide Weather Forecast  

A highly anticipated change is on the horizon as weather models continue to advertise a significant pattern shift and snowfall to begin tonight. By Tuesday morning, if the forecast verifies, we expect avalanche conditions to change and danger to ramp up more by the end of the week. The amount of new snow received and wind accompanied with the two storms forecasted will keep us on our toes each day as this evolves. The snowpack throughout the Southern Mountains is queued up for potentially the first real tolerance test of the season as November was not a big moisture producer. 

The majority of our snowpack, accumulated in the month of October is now faceted and weak at the surface and also within the pack on northerly-facing slopes. Above treeline, east and west aspects offer firm- crusted surfaces overlying weak-faceted snow and older crust layers below. Time will tell, but it will likely not take much of a new load to produce avalanches that step deeper into the foundational snowpack.  

In addition, the snow on north-facing slopes, near and below treeline is also very weak. Those slopes hold loose, cohesionless snow from the surface to the ground. This lack of structure becomes more problematic on steep rolls or creek banks where the weak surface facets are likely to sluff from the weight of a rider and will gain mass while moving downhill. We expect these facet sluffs to remain small in size, but if caught, the consequences could yield a rough ride through shallowly buried obstacles. 

Although the start to the season appears bleak, keep in mind that bare ground or patchy snow-covered terrain provides a clean slate. Those slopes will not have old snow layers lurking below and should offer safer options as new snowfall is added. Patience and careful terrain selection will be crucial moving forward this week and awhile beyond.  

 


  • Well developed faceted snow crystals makeup the majority of the snowpack. North San Juan 11/28/21 (full)
  • Wind-drifted pillows scattered along gully features and rocky outcrops in steep terrain. North San Juan 11/28/21 (full)
  • Once we isolated the column and compensated the tensile strength of the slab, we observed propagating results and sudden planar fractures in stability test where a thick, wind-drifted slab rest above weaker snow. We did not observe any other signs of instability on this slope. On the margins of the slab, the snowpack was shallower and mostly faceted. South San Juan. November 26, 2021. (full)
  • Dribs and drabs of snow combined with prolonged stretches of warm, sunny days and clear, cold nights drives the perfect facet factory. Not a problem now, but this fragile structure will be susceptible to avalanching once a new load is added. South San Juan. November 26, 2021. (full)

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Avalanche Observations
No relevant backcountry observations found for this forecast

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Field Reports
Report Date Observer Snowpack Obs Avalanches Media
View Mon Dec 6 Jeremy Primmer No No Yes (4)

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Weather Observations
Station Date Time Temperature Relative Humidity Wind Speed Wind Direction Max Gust 24 Hr Snow
Hayden Pass Mon Dec 6 7:00 PM 31 - - - - -

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