THIS AVALANCHE ADVISORY EXPIRED ON March 2, 2017 @ 5:38 am
Avalanche Advisory published on March 1, 2017 @ 5:38 am
Issued by Andy Bond - Taos Avalanche Center

Avalanche danger is CONSIDERABLE near and above treeline.  Avalanche danger is MODERATE below treeline.  The storm slab avalanche problem continues today.  Backcountry travelers should not be surprised by human triggered avalanches at any elevation today.  Dangerous avalanche conditions exist.  Cautious and conservative terrain decisions and route selection are necessary today.

 

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
  • 1. Low
  • 2. Moderate
  • 3. Considerable
  • 4. High
  • 5. Extreme
Avalanche Problem 1: Storm Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Storm totals are in the  18 - 30" range with over 3" of SWE.  Strong WSW winds during the storm, gusting into the mid 60s have loaded slopes in the alpine, where storm slabs could be 4 to 6 feet thick. This new snow fell on a variety of hard, smooth crusts as well as low density snow from Monday morning, and will struggle to bond to these underlying surfaces. This has created widespread instability as this new load needs time to settle and adjust.    

Carefully evaluate the snowpack and terrain as you travel.  Signs of recent avalanches, "whumphing" collapses and shooting cracks are indications of an unstable snowpack.  If you observe any of these bulls-eye clues, adjust your travel to lower angle terrain. 

advisory discussion

Not a bad way to end a pretty disappointing February!  Storm totals ranged from 18 - 30" of new snow with about 3" of Snow Water Equivalent (SWE). Strong SW winds gusting into the 60's also accompanied this storm adding to storm totals especially above treeline. The storm finally made it's exit Tuesday evening as winds started to subside.  Monday's 4+/- inches of snow came in cold and light,  and is now capped by another two feet or more of wind effected, denser new snow from Monday Night/Tuesday.  This has created areas of an "upsidedown" surface snowpack - an unstable situation. See Video from Tuesday!

These storm slabs should become more stubborn than yesterday to trigger as the 2' plus of storm snow settles and consolidates.  But this takes time and today is not the time to push things.  Observations from ridgetops are limited but there was a report of a 4 foot natural avalanche from Tuesday.  Slabs below ridgetops could be pushing 4 to 6 feet thick in spots from the strong WSW winds during the storm.  These slabs are sitting on firm hard crusts formed from the hard freeze after warm temperatures earlier last week and strong winds that proceeded this storm. Any avalanche triggered could run long distances on these smooth surfaces.  North facing shallow areas in the trees near treeline were not impacted from the warm temperatures earlier in the week and have an overall poor snowpack structure with basal facets still lurking on the ground.  These slopes should be approached with extra caution as the weight of a smaller storm slab avalanche could be enough weight to step down into these older layers.

Today will be a sunny nice day, with the first real powder skiing in a long time.  Don't let powder fever get the better of you.  The avalanche danger is  CONSIDERABLE on all aspcets near and above treeline. Human triggered avalanches are still likely today and could be very large and destructive.  Today is not the day to throw caution to the wind.  Careful snowpack evaluation, cautious route finding, and conservative decision making are essential today.  Be safe out there today all!

 

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

Tuesday was an active day with widespread "whumphing" collapses and shooting cracks as well as remote triggering storm slab avalanches.  18 to 24" of snow was observed while touring in the Williams Lake Area.  Snow fell all day ending in the afternoon evening hours with graupel.  We stayed below and near treeline but the strong winds could be heard howling up above us.  The snow that fell Monday night into Tuesday had some body and weight to it even though it was still pretty low density.  This subtle density difference between the couple of inches of snow that fell in the morning on Monday was all that was needed to create a weak layer.  We were remote triggering storm slab avalanches from 100 yards away that typically were wanting to run on slopes 35° or steeper. Peak instability seemed to be around the mid morning hours on Tuesday.  Visibility was such that we weren't able to get great observation from above treeline but there were reports from inbounds of 4' natural storm slab avalanches.  All indications were that it was just the new storm snow running on the old snow interface. Wednesday should provide us with better visibility and the ability to get better observations.   

Monday brought us an unexpected 3-5 inches of low density snow in the mountains, accompanied by strong W winds.  These winds were building touchy ridgetop cornices and creating unstable surface conditions on steep rollovers and convexities.  Check out Andy's video explaining Monday's findings.   We found the new snow was not bonding well to the underlying crusts, and although there was not much weight to move around yesterday, that will certainly change today with more snow and wind.

Below the new snow surface lies a variety of melt freeze and wind crusts, coupled in many places with a layer of facets (see pics below).  Stability tests from recent days suggest this faceted layer is willing  to propagate and we suspect it will do so with the added weight of today's storm slabs.

Deep layers of concern in the snowpack have shown signs of healing, and we have not been able to initiate failure of these layers since last week's melt/ freeze cycle.  See Graham's video from Friday about this.  This is reassuring but areas of weak snow may still linger on isolated terrain features, mostly rock ribs and thin spots. 

Pic: Small storm slab avalanche that we remote triggered 100 yards away

Pic: Snow pit showing the low density snow from Monday morning, with the slightly denser storm snow sitting on top.  Avalanche debris above the pit that we triggered from below.

Pic: 2' Storm Slab crown on a NE aspect near treeline

Pic: Some of the widespread collapse and shooting cracks we were getting yesterday in our travels.

 

 

 

 

 

 

Weather and CURRENT CONDITIONS
weather summary

The potent storm from Tuesday made its exit last night ushering in Sunny skies for today.  A NW flow will keep temperatures relatively cool (mid 20's to 32°F).  WInds should back off today out of the NW (10 - 20 MPH).  A cold clear night is on tap for tonight as temperatures look to warm up slightly for Thursday.  High pressure and sunny skies are in the forecast for the foreseeable future.  But we'll take what this last storm delivered!

Weather observations from the Wheeler Peak Wilderness between 9000 ft. and 13000 ft.
0600 temperature: 1.8 deg. F.
Max. temperature in the last 24 hours: 19.2 deg. F.
Average wind direction during the last 24 hours: WSW
Average wind speed during the last 24 hours: 26 mph
Maximum wind gust in the last 24 hours: 61 mph
New snowfall in the last 24 hours: 10.5 inches
Total snow depth: 95.6 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 Sunny
Temperatures: high to 34 deg. F. low to 9 deg. F. high to 38 deg. F.
Wind Direction: W W W
Wind Speed: 5 - 15 5 - 10 5 - 10
Expected snowfall: 0 in. 0 in. 0 in.
For 11000 ft. to 13000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly Sunny Mostly Clear Sunny
Temperatures: high to 22 deg. F. low to 7 deg. F. high to 32 deg. F.
Wind Direction: NW NW NW
Wind Speed: 10 - 20, shifting to W and dropping to 5 to 10 5 - 15 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.