THIS AVALANCHE ADVISORY EXPIRED ON February 18, 2017 @ 5:26 am
Avalanche Advisory published on February 17, 2017 @ 5:26 am
Issued by Andy Bond - Taos Avalanche Center

MODERATE avalanche danger remains above treeline due to recently formed wind slabs. Human triggered wind slab avalanches are possible today.  Persistent slabs above treeline are still a concern, especially in shallow areas with weak sugary snow near the ground. LOW avalanche danger exists near and below treeline.  Warm, sunny weather today could produce loose wet avalanches on solar aspects in the afternoon.

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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    Very Likely
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Winds earlier in the week were swirling in the upper and mid elevations, building isolated slabs on a variety of aspects, and reaching down into near treeline areas in places.  Look for signs of recent wind loading like wind drifts, wind pillows and ripples on the snow surface to help identify areas where wind slabs may exist (See Video from Thursday).  Even a small avalanche in high risk terrain could mean big consequences.

Avalanche Problem 2: Persistent Slab
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The snowpack structure remains shallow and weak in isolated areas, with small grained facets buried below a hard slab. This past week we've found shallow areas that still have basal facets on the ground.  See the video from Wednesday.   A smaller wind slab avalanche or a falling cornice might be enough weight to step down into these older layers. It's a good idea to investigate the slope you plan to play on by digging a few pits and identifying if these weak layers are able to propagate.  Areas of concern are likely trigger points, near rocks and shallower areas. Be aware of warming temps on solar aspects where a skier or rider could impact further down into the snowpack.  See Advisory Discussion for more discussion.

advisory discussion

Our main concerns today are wind slabs formed earlier in the week in the upper elevations, and a lingering persistent slab problem.  Investigate the snowpack to confirm or deny the presence of weak snow under these slabs.  The chances of triggering a persistent slab are low, but the consequences are high, as these could be large and destructive avalanches. It was nice to talk with an avalanche educator from Utah yesterday who spent the last couple of days in our backcountry.  Our persistent slab problem is there and although our faceted weak layers are starting to heal and round, we are still dealing with facets.  Facets are hard to trust and strong winds have produced hard slabs above these facets at varying depths.   I like how Jake put it, in that it's a game of Russian Roulette where we have an 18 chamber gun and only 1 bullet. The likelihood is low right now but the consequences would be incredibly high.  Our spatial variability compounds this as hitting that "sweet spot" or trigger point can be easier as our snowpack depths vary.  (See Photo Below).  We don't have many human triggers the way Utah and Colorado do where evidence of these layers being a problem is easier to see. It's a good thing that people aren't triggering avalanches, but don't get lulled into thinking these layers still aren't a concern.  We've left the avalanche danger at Moderate above treeline where human triggered avalanches are possible largely due to high consequence of these persistent slabs if you were able to trigger one.   

This is an old crown that I found last Friday in South Fork Drainage on SE aspect around 12,200'.  This ran on basal facets probably two weeks ago.  I know that it's hard to see but the depths vary greatly in the crown from 8" to 5'.  This speaks to our varability where a skier or rider won't know that the depth to the weak layer is going to vary greatly!

With warming temps and direct sun today, loose wet snow avalanches are possible by afternoon.  These will mostly be small slides, confined to the new snow that fell earlier in the week.  Watch for roller balls and pinwheels especially on steeper slopes, indicating it's time to get off the sunny slopes.

 

We are going to do another avalanche talk this Wednesday February 22nd at 6PM at Taos Mesa Brewing (Mothership).  The talk this week will be a season snowpack review and hopefully a productive discussion about backcountry rescue and the challenges we have here in Northern New Mexico.

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.

Need to brush up on your beacon skills?  Check out the NEW beacon practice problem we have out at Taos Ski Valley.  This is a new beacon problem for the week of 2/14 - 2/21. High pressure is a great time to get some training in before our next storm this weekend.  Thank you Taos Ski Patrol for your continued support!  We will switch the problem up on Monday or Tuesday - stay tuned.

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

On Thursday we were able to spend some time above treeline.  Recent winds have done a number on the snowpack from the little bit of snow that fell on Monday.  For the most part these wind slabs were isolated and easy to identify.  They ranged from hard hollow sounding to softer more pillowed wind slabs.  Warm temps should help to heal these wind slabs but in our stability tests we were able to initiate failure and propagation.  We were finding near surface faceting that is not a problem now but could be with this next incoming storm.  We felt comfortable skiing corn on an East aspect around 9:45AM.  Being this far south the sun can warm things up quickly in a hurry even in the middle of February.

Warming temps and sun have been a common story in the mountains the last couple of days.  We didn't receive the expected snowfall amounts on Monday, and the snow that did fall got hammered by wind.  My partner and I explored the effects of recent winds on Wednesday on Bull of the Woods Mtn (on the Red River side).  We found very hard (pencil and knife hard) wind slab from the season's prevailing WSW winds near the ridgetops, and recent uphill drifts from E, SE, and NE winds earlier in the week.  Check out the video, and pics below.  Basal depth hoar near the ground was present in our pits on E and N aspects, although these large crystals are slowly healing, and we were not able to initiate failure or propagation in our stability tests. The slabs seem to be bonding well in most places, but our conservative approach kept us off of recently wind loaded, steeper slopes.  We also found a recently formed layer of near surface facets just below the capping wind crust at the surface.  We will keep an eye on this potentially weak layer as we get more snow (hopefully this weekend).

Tuesday's warm temps and sunny skies warmed the snow surface on solar aspects, but a very hard crust from previous days persisted in most places.  I investigated a West aspect on the Wheeler ridgeline and found noisy skiing atop a 2" sun crust.  Pit digging revealed a warm, wet snowpack on this aspect, proof that recent warm temps had penetrated throughout the pack.  Isolated wind slabs formed from recent NE winds lurked in depressions and rollovers, but were stubborn and seemingly bonding well.  I did find a layer of near surface facets forming in shadier areas that lacked a consistent sun crust.

pic; ENE aspect @ 11,700ft showing signs of lots of recent wind from several directions.

pic below: uphill drifting from ENE winds

 

 

pic: Wind slab on a NE aspect around 11,500' from Thursday

 

 

 

 

 

 

Weather and CURRENT CONDITIONS
weather summary

Another warm day is on tap, with partly cloudy skies and temps into the 40s and 5 to 10 MPH winds out of the NW.  Another small inversion this morning where temperatures at 12,400' are warmer than 9200'.  A warm, wet storm system approaches our area Saturday Night and Sunday.

 

Weather observations from the Wheeler Peak Wilderness between 9000 ft. and 13000 ft.
0600 temperature: 23.6 deg. F.
Max. temperature in the last 24 hours: 37.3 deg. F.
Average wind direction during the last 24 hours: NW
Average wind speed during the last 24 hours: 7 mph
Maximum wind gust in the last 24 hours: 27 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 72.4 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Albuquerque NWS
For 9000 ft. to 10000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy Partly cloudy Mostly cloudy
Temperatures: high to 47 deg. F. low to 24 deg. F. high to 45 deg. F.
Wind Direction: NW W SW
Wind Speed: 0-10 5-10 5-10
Expected snowfall: 0 in. 0 in. 0 in.
For 11000 ft. to 13000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy Partly cloudy Mostly cloudy
Temperatures: high to 42 deg. F. low to 21 deg. F. high to 38 deg. F.
Wind Direction: NW W SW
Wind Speed: 5-10 5-10 5-10
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.