THIS AVALANCHE ADVISORY EXPIRED ON March 13, 2017 @ 5:06 am
Avalanche Advisory published on March 12, 2017 @ 5:06 am
Issued by Andy Bond - Taos Avalanche Center

Human triggered persistent slab avalanches remain possible today above treeline on NW through E aspects as MODERATE avalanche danger exists above treeline. LOW avalanche danger exists near and below treeline. A buried layer of facets in the top few feet of the snowpack continues to be a concern above treeline.  With rapidly rising temps and the strong spring sun wet snow avalanches could become a concern on sunny aspects and low elevation slopes.  

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: Persistent Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

With more and more time passing since our last storm, it is becoming more difficult to trigger an avalanche. The snowpack has slowly been gaining strength with the recent warm temperatures. There are still slopes above treeline on northwest through southeast aspects that have a 2 to 4 foot cohesive slab resting on a layer of weak, sugary facets and/ or a crust/ facet combo.  While triggering an avalanche will be difficult, if you find that "sweet" spot on the wrong slope you could trigger a large and destructive avalanche.  Suspect areas include thin, rocky spots where the weak layer is closer to the surface.

advisory discussion

Strong winds have decimated our snowpack in spots especially on west and southwest slopes. Areas that weren't completely scoured have hard firm surfaces that thankfully have been softening up with the recent warm temps.  Although it feels like spring, we still have cold snow in our snowpack above treeline.  In many areas we have layer of small grained facets that is now buried by a 2 to 4 foot slab. On solar aspects this weak layer of facets is associated with a crust, with faceting above and below. Shadier aspects it is just small grained facets. Recent warm temperatures are helping to heal these facets, but stability tests continue to indicate that you can initiate collapse and propagation of this weak layer.  While the chances of triggering this slab will be difficult, it is certainly possible, especially in likely trigger points like shallow, rocky areas where the weight of a skier or rider is more likely to collapse the weak layer.  

Careful evaluate the zone you plan to play in.  Dig down to see if you have a reactive layer of facets under a slab, and adjust your terrain choices accordingly.   

MODERATE avalanche danger remains above treeline today, while near and below treeline areas have a LOW danger.  Afternoon warming and the strong sun could raise the avalanche danger in the form of loose wet slides, as the snow surface turns to slush on all but the shadiest slopes.  Obvious signs like snowballing and pinwheeling tell us it's time to find shadier slopes once the midday heat sets in.  A small loose wet slide may be enough of a trigger to step down into deeper weak layers, producing larger, more destructive avalanches.

Many of you have been asking and we are going to be teaching a Level 1 avalanche class Friday March 31st - Sunday April 2nd.  For more information please email Andy or Graham at andy@taosavalanchecenter.org or graham@taosavalanchecenter.org

With this week of high pressure, it's great time to practice your avalanche beacon skills with our new weekly beacon practice problem at TSV!

If you're interested in how much snow we've gotten this year check out our recent blog post.  This was written before this last storm, so add 25.5" of snow and 3.15" of SWE to the totals from February which should bring us right around average!

If you get into the backcountry, please drop us a line at Taosavalanchecenter@gmail.com or on the "Submit Observations" tab at the top of the homepage.  Your field observations are extremely helpful, no matter how simple, and we thank all of you who have shared.

If you're looking to get some exercise and support a great cause look into the Ben Myers Ridge-A-Thon.  This event has been going on now for 20 Years. Come hike the ridge at Taos Ski Valley March 17 & 18th and raise some money that benefits our community!

recent observations

We avoided rain on Saturday and warm temperatures have produced melt-freeze and sun crusts at low and mid elevations.  Shady aspects in the trees still have softer powder, but skiing can be tricky endeavor right now.  Daylight saving should allow us to get a little later start when chasing corn.  Although we have had warm temperatures we are still finding cold snow below the surface above treeline.  Stability tests are indicating that the weak layer of buried small grained facets are healing but are still a concern above treeline and still need a little bit more time before they are no longer a concern.

Warm weather, strong sun, and light winds made Thursday a beautiful day.  Our snowpack notices changes in the weather like this, like the melting of surface layers and the potential healing of buried weak layers.  Observations from Thursday include limited loose wet slide activity, as one regular observer noted "the upper layer goes pretty easy with a push but didn't see any natural activity, though it was pretty punchy in the trees". 

Beautiful spring weather made for pleasant traveling the last few days and many folks got out into the backcountry.  Observations from ridgetops are consistent with those at lower elevations - a buried layer of facets 1-3 feet down is present in most places (video).  Many slopes also have a hard crust or two associated with this faected layer, providing a smooth sliding surface for the overlying persistent slab.  Stability tests results indicate this faceted layer is willing to propagate with a moderate amount of force.  A regular observer found this facet/crust combo on a SE aspect on Wednesday, and noted good corn skiing and the beginnings of wet loose activity in the afternoon. 

Pic; pit from Wed, N aspect at 11,600ft

Pic; Graham checking out the wind scoured ridgeline

 

Weather and CURRENT CONDITIONS
weather summary

A ridge of high pressure is keeping all the moisture well to our north.  Temps will remain warm today reaching the mid 50's at 9000'.  Winds will be moderate (10-25 MPH) out the west that should cool things down slightly. There's no snow on the horizon as we'll settle into a spring melt-freeze cycle for the next ten days.  

Weather observations from the Wheeler Peak Wilderness between 9000 ft. and 13000 ft.
0600 temperature: 20.4 deg. F.
Max. temperature in the last 24 hours: 38.5 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 35 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 83.6 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Albuquerque NWS
For 9000 ft. to 10000 ft.
Sunday Sunday Night Monday
Weather: Mostly Sunny Mostly Clear Mostly Sunny
Temperatures: high to 56 deg. F. low to 27 deg. F. high to 57 deg. F.
Wind Direction: W NW W
Wind Speed: 5-25 5-20 decreasing to 5-10 after midnight 5-15
Expected snowfall: 0 in. 0 in. 0 in.
For 11000 ft. to 13000 ft.
Sunday Sunday Night Monday
Weather: Partly cloudy in the morning then clearing Mostly Clear Mostly Sunny
Temperatures: high to 43 deg. F. low to 23 deg. F. high to 45 deg. F.
Wind Direction: W NW W
Wind Speed: 10-25 5-20 5-15
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.