THIS AVALANCHE ADVISORY EXPIRED ON March 9, 2017 @ 5:41 am
Avalanche Advisory published on March 8, 2017 @ 5:41 am
Issued by Graham Turnage - Taos Avalanche Center

Human triggered persistent slab avalanches remain possible today.  MODERATE avalanche danger exists near and above treeline, while below treeline areas have a LOW danger.  A buried layer of facets in the top few feet of the snowpack is capped by a persistent slab in many places.  Carefully evaluate snowpack and terrain before committing to any slopes, identifying where this avalanche problem may exist.

 

2. Moderate

?

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

2. Moderate

?

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

1. Low

?

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

Many areas near and above treeline have a 2 to 4 foot cohesive slab resting on a layer of weak, sugary facets and/ or a crust/ facet combo.  Stability tests indicate that these weak layers are still willing to propagate. While triggering this slab will not be a common occurrence, 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.  

Dig down in the snow and look for the presence of these weak layers, they are pretty easy to identify right now (see pic in Recent Obs below).  It doesn't take much time, and is going to be the only way to know if the slopes you plan to ski or ride have this questionable snowpack structure.    

advisory discussion

MODERATE avalanche danger exists above and near treeline today, while below treeline areas have a LOW danger.  Remember a Moderate danger indicates that human triggered avalanches are possible.  A layer of low density facets is now buried by a 2 to 4 foot slab on many slopes at mid and high elevations. In some areas this weak layer of facets is associated with a smooth crust, with faceting above and below.  Stability tests continue to indicate that you can initiate collapse and propagation of this weak layer.  While the chances of triggering this slab will not be widespread, 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.  Monday's wind capped the snowpack with a firm, semi-breakable / semi-supportive wind crust and thin wind slabs.  These surfaces will further insulate the buried weak layer of facets in some places - but not all.  This speaks to an increasing spatial variability in our snowpack, suggesting careful evaluation in the zone you plan to play in.  Dig down to see if you have a reactive layer of facets under a slab.....and heed those warnings if so.

Persistent slab problems are exactly that - persistent, and these weak layers take time to heal. Cold temperatures are delaying this healing process.  These conditions are capable of producing potentially large and destructive avalanches, and require careful evaluation of snowpack and terrain.  The existance of a buried layer of facets underlying a denser slab should make us all travel conservatively, and carefully evaluate each slope with a fresh set of lenses.  We are back in the zone of "if you happen to trigger this slab, the consequences could be high".  

SORRY GANG, WE ARE NOT GOING TO BE DOING AN AVALANCHE AWARENESS TALK THIS WEDNESDAY.  WE'LL KEEP YOU POSTED WHEN THE NEXT AVALANCHE TALK WILL BE.

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!

We have a fresh beacon problem out at TSV for the week of feb 28 - mar 6 - check it out and keep your beacon skills sharp!  We will change it up on Wednesday, stay tuned!

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

Monday's wind left it's mark on the snow surface.  With gusts up to 80mph and sustained winds in the 60s,  most mountain locations saw quite a bit of destruction.  Lower elevations have limbs and debris scattered like the aftermath of a hurricane, while upper elevation slopes got scoured to bare rock in many places (see pics below).  On Tuesday my partners and I toured around the Williams Lake / Lake Fork area to inspect the damage.  We consistently found a snowpack which houses a weak layer of sugary facets 2-3 feet down, some coupled with an old melt/freeze crust (pic below).  We made a quick video explaining our findings.  Stability tests indicate this layer is willing to propagate with sudden collapses under a moderate amount of force.  Ridgeline areas were pummeled by Monday's wind, as shown in the photo below.  See video of Graham doing an ECT on a NE aspect around 11,800'.

Pic; No Name ridge raked clean of snow - no that's not a crown up top, just some gnarly wind scouring

 

 

pic; careful on your low elevation exits - woody debris everywhere!

 

 

 

Weather and CURRENT CONDITIONS
weather summary

Warm temps and sunny skies are the story for today - and the next few days.  Temps top out close to 50 F at 9000ft and winds should be out of the West at 10-30mph.  Overnight lows look to be around 25, and as our friends at the Nat'l Weather Service said this morning; "Otherwise, above normal temperatures and little to no chance for measurable precipitation is expected for the foreseeable future".

Weather observations from the Wheeler Peak Wilderness between 9000 ft. and 13000 ft.
0600 temperature: 20.2 deg. F.
Max. temperature in the last 24 hours: 23.7 deg. F.
Average wind direction during the last 24 hours: WSW
Average wind speed during the last 24 hours: 19 mph
Maximum wind gust in the last 24 hours: 29 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 87.5 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Albuquerque NWS
For 9000 ft. to 10000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly Sunny Mostly clear. Mostly Sunny.
Temperatures: high to 50 deg. F. low to 25 deg. F. high to 55 deg. F.
Wind Direction: W W W
Wind Speed: 5-25 5-15 5-15
Expected snowfall: 0 in. 0 in. 0 in.
For 11000 ft. to 13000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly Sunny Mostly clear. Mostly Sunny.
Temperatures: high to 40 deg. F. low to 20 deg. F. high to 43 deg. F.
Wind Direction: W W W
Wind Speed: 10-30 10 -25 5-20
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.