THIS AVALANCHE ADVISORY EXPIRED ON March 5, 2017 @ 5:47 am
Avalanche Advisory published on March 4, 2017 @ 5:47 am
Issued by Graham Turnage - Taos Avalanche Center

MODERATE avalanche danger exists at all elevations. Human triggered persistent slab avalanches remain possible today near and above treeline. Below treeline and on solar aspects wet loose avalanches will become possible as the temperatures begin to warm.  Evaluate each slope independently and assess to see if weak, sugary facets are present beneath a persistent slab.  Manage terrain choices accordingly.

2. Moderate

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

2. Moderate

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

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    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
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A buried layer of facets formed last week (pre-storm) exists under a persistent slab on many slopes at mid to high elevations.  This 2-4 foot slab is relatively soft (4F/1F) in most places, but its is still showing signs of cohesivity where coupled with a buried weak layer.  On slopes that have seen even just a bit of sun, there is also a crust associated with this faceted weak layer. These density differences have created a strong over weak snowpack - never a comforting situation.   Most of the widespread avalanche activity on Tuesday and Wednesday ran on this layer.  (see pic below)

Avalanche Problem 2: Loose Wet
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Temperatures will warm significantly today coupled with strong solar input.  This will raise the afternoon avalanche danger with the possibilty of wet loose slides on sunny slopes at mid elevations all aspects below treeline.  As the snow surface starts to turn to mush and starts snowballing and pinwheeling, it's time to retreat to colder slopes.

 

advisory discussion

Remember that a MODERATE avalanche danger carries with it the possibility of human triggered avalanches.  A layer of low density factes 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 providing a nice sliding surface for that slab.  Stability tests are indicating 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 shallow areas where the weight of a skier or rider is more likely to collapse the weak layer.  These conditions are very capable of producing potentially large and destructive avalanches, and require careful evaluation of snowpack and terrain.  Dig down a few feet and see if this layer of facets exists on the slope you plan to play on, and see if it has a williingness to propagate.  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".  

As we get new snow in March, our strong sun combined with warming temperatures following storms will make Loose Wet avalanches more of a concern. Today will be another warm day with temperatures reaching the mid 40's below treeline and high 30's at higher elevations.  Expect to see roller balls below treeline and on steep solar aspects as the day starts to warm.  This problem can be easily avoided by sticking to shady aspects

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!

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

On Friday my partners and I toured up into Long Canyon to investigate the week's snowpack changes.  Check out the video.  We saw evidence of several fairly widespread natural slab avalanches that ran on a buried layer of facets and a crust/facet combo (see pic below).  We suspect these slides released Tuesday during the storm's peak instability, as the crowns are almost covered by subsequent snow, as shown in the photo below.  Propagation saw tests (PSTs) and Extended Column Tests (ECTs) were consistently showing the buried weak layer of facets are suspect, with sudden collapses and full columnar propagation the norm.  PST results were in the 30/100 cm range, and ECT scores were in the teens and low 20s, with full propagation.  We noted that while it would not be likely to trigger these slabs on all slopes, areas of concern are shallow, rocky rollovers and steep convexities.  Solar aspects were getting wet and just starting to pinwheel around noon and we avoided afternoon sunny slopes with respect to the chances of wet loose slides.

On Thursday Andy made this video explaining the slab/ crust situation in the higher elevations - still very relavent for this weekend.

Lower elevation slopes have a mixed bag of snowpack structures, and these warm temps today will continue to change that.  Weak, unconsolidated snow can be found on many slopes below treeline, and are suspect of wet loose slides.  Afternoon exits from the high country are tricky this week, as the warm temps are turning the lower elevation snow surface to complete mush.  Ski and skin wax recommended!

Pic; look closely to see old crown in the pillow just below the ridgetop.  These slides from Tuesday's storm had widespread propagation and ran on buried facets and crusts formed last week.  Crowns are almost covered by subsequent snow, but are 2-3 feet in most places.

 

Pic; pit from Friday, ENE aspect at 11,700ft.  Buried weak layer of facets sitting below crust about 2 feet down.

 

Pic: Snowpit from a North Aspect near treeline on Thursday.  The storm slab is 92cm thick with 4F to F hard snow.  I marked the weak lower density snow that is still there from Monday morning.  ECTP 15 SP where the line is marked.

 

 

 

 

 

Weather and CURRENT CONDITIONS
weather summary

The warming trend continues today across the area with decreasing clouds giving way to mostly sunny skies. Winds will pick up Sunday, with downslope warming sending temperatures well above normal. A cold front will push through Monday, with windy conditions as temperatures cool down behind the front, but a new warming trend will begin Wednesday and continue through the end of next week with highs reaching above normal areawide as early as Thursday.

Weather observations from the Wheeler Peak Wilderness between 9000 ft. and 13000 ft.
0600 temperature: 22 deg. F.
Max. temperature in the last 24 hours: 30 deg. F.
Average wind direction during the last 24 hours: WSW
Average wind speed during the last 24 hours: 14 mph
Maximum wind gust in the last 24 hours: 25 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 90 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Albuquerque NWS
For 9000 ft. to 10000 ft.
Saturday Saturday Night Sunday
Weather: Sunny Mostly Clear Mostly Sunny
Temperatures: high to 47 deg. F. low to 25 deg. F. high to 47 deg. F.
Wind Direction: W SW SW
Wind Speed: 5 - 20 5 - 25 10-25
Expected snowfall: 0 in. 0 in. 0 in.
For 11000 ft. to 13000 ft.
Saturday Saturday Night Sunday
Weather: Sunny Mostly Clear Mostly Sunny
Temperatures: high to 39 deg. F. low to 20 deg. F. high to 37 deg. F.
Wind Direction: W W SW
Wind Speed: 10-25 15-30 20-35
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.