THIS AVALANCHE ADVISORY EXPIRED ON December 24, 2017 @ 5:57 am
Avalanche Advisory published on December 23, 2017 @ 5:57 am
Issued by Andy Bond - Taos Avalanche Center

Moderate avalanche danger exists today above treeline due to wind slab avalanches.  Recent snow and moderate to strong west winds last night and today will make human trigged wind slab avalanches possible today.  Low avalanche danger exists near and below treeline.  Evaluate the snowpack and terrain carefully. Identify and avoid areas where wind slabs may exist

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

1. Low

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Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
  • 1. Low
  • 2. Moderate
  • 3. Considerable
  • 4. High
  • 5. Extreme
Avalanche Problem 1: Wind Slab
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    Certain
    Very Likely
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    Unlikely
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    Small

Overnight, winds picked up out of the SW.  With 3 to 6" of low density snow from Thursday night available for transport, expect to find small wind slabs below ridgelines and in cross loaded gullies above treeline.  6 to 8 inches of wind loaded snow should be approached with caution. Pay attention to obvious signs of wind slab instability like cracking, shooting cracks, or hollow drummy sounding slabs as these are indications that you've found a wind slab

Winds picking up last night:

Avalanche Problem 2: Persistent Slab
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    Certain
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    Very Large
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Higher elevation (conservatively above 11,000') northerly aspects has the deepest snowpack (1 to 3 feet) in our forecast area.  The snowpack on these slopes are highly variable but do contain some form of slab/weak layer combination.  It's a good idea to dig down into the slopes you plan to travel on to assess if this weak snow pack structure exists.  This won't take much time and is easy to identify with a gloved hand.  The faceted weak layers are easy to push against and the crusts/slabs will be a lot firmer.  Be aware that a smaller wind slab avalanche has the potential to step down into these deeper layers.  

Photo: An example of what to look for above treeline on North Aspects

advisory discussion

It sure was nice to see the mountains painted in white again!  3 to 6" of low density snow (.3" of snow water equivalent SWE) fell Thursday night with not much wind.  This snow fell on a variety of surfaces ranging from icy crusts, facets and bare ground.  Yesterday was maybe a little bullish in upping the avalanche danger to Moderate.  However, with snow available for transport and west winds picking up overnight and throughout the day today, human trigged wind slab avalanches will be a very real possibillity.  This will mostly be confined to ridgelines and crossloaded gullies, but be aware of open terrain near treeline that is impacted by drifting snow.    

An early season thin snow pack that is highly variable always warrants caution.  Higher elevation northerly aspects has a poor snowpack structure. Check out Andy's Video from Thursday about the snowpack structure on these slopes.   Just because we have all the ingredients for an avalanche doesn't always mean that slope will avalanche.  The best case scenario for this early season snowpack is to get a big storm (like last December) that will give these weak layers a big test and hopefully produce avalanches allowing us to start from the ground up.  The current situation is that we add a little bit of weight (.3" of SWE) either through storms or with wind loading.  What makes this scenario so difficult is that it's hard to forecast how much stress these weak layers can take.  It's best to take a conservative approach to these slopes and assume these slopes have the potential to slide as we wait for a big storm to give these weak layers a big test.   

It's great to see snow in the mountains!  But we still have a thin snowpack and hazards exist under the snow.  Winter only officially started yesterday and hopefully 2018 will bring more snow.  If you're interested in snow science, right now is a great time to get outside and dig some snow pits on northerly aspects above 11,000' .  You don't need to be in avalanche terrain to get a great idea what the snowpack is like.  The striations in the facets are easy to see with just your eyes.  It's also a great time to practice stability tests as we have a lot of weak layers and interesting results right now.  If you get out send us your observations, so that we can produce a better product!    

 

The Albuquerque National Weather Service is providing us with a Backcountry Recreational Forecast again this year. Check in daily for your mountain weather forecast.

recent observations

Travel is still dificult to impossible on skis at lower elevations.  The 3 to 6 inches of low density snow from Thursday night was quickly settling out at lower elevations and melting away on southerly aspects.  The deepest snow can be found on northerly aspects above 11,000' where a 1 to 3' snowpack exists.  It's on these slopes that recent snow has fallen on a variety of surfaces ranging from crusts to facets.  On east, south and west aspects the new snow was falling on bare ground. Overall this new snow is not bonding well and will be available for transport when winds do pick up.    

Northerly aspects above treeline contain a deeper snowpack, these slopes will look the most enticing to make a turn.   It's on these slopes that you'll find depth hoar on the ground and several crust/facet combinations.  We have alot of variablity in the snowpack and not one snowpit has looked the same.  But what we are finding is a poor overall snowpack structure with several faceted weak layers showing a propensity to propagate.    

Photo: A small wind slab on a NNE aspect above treeline with faceted snow beneath

 

Weather and CURRENT CONDITIONS
weather summary

Today will bring warmer temperatures and lots of sun.  Temperatures should get above freezing at 10,000'.   Moderate to strong west winds (10 - 30 MPH Gusting 45 MPH) will be with us throughout the day.  The next several days will bring a repeating trend of warming temperatures during the day with lots of sunshine and night time temperatues dropping well below freezing.  We'll stay positive but it could be 2018 before we see any significant moisture coming our way.   

Weather observations from the Wheeler Peak Wilderness between 9000 ft. and 13000 ft.
0600 temperature: 9.3 deg. F.
Max. temperature in the last 24 hours: 14.3 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 20 mph
Maximum wind gust in the last 24 hours: 36 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 7.4 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Albuquerque NWS
For 9000 ft. to 10000 ft.
Saturday Saturday Night Sunday
Weather: Mostly Sunny Mostly Clear Mostly Sunny
Temperatures: 36 deg. F. 18 deg. F. 38 deg. F.
Wind Direction: W W W
Wind Speed: 15-30 5-25 5-20
Expected snowfall: 0 in. 0 in. 0 in.
For 11000 ft. to 13000 ft.
Saturday Saturday Night Sunday
Weather: Mostly Sunny Mostly Clear Mostly Sunny
Temperatures: 24-30 deg. F. 16 deg. F. 27-33 deg. F.
Wind Direction: W W W
Wind Speed: 10-30 10-30 10-20
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

This advisory applies only to backcountry areas outside established ski area boundaries, Click here for a map of the area. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the Taos Avalanche Center who is solely responsible for its content.