Taos Region

Moderators: mark, scotthsu, Bob, Matt

Re: Taos Region

Postby JBella » Mon Dec 03, 2018 11:13 pm

Storm totals ranged from 8 to 14 inches by midnight <22.25 hours ago. Don't have much info, will add some after we get out to check things out. Lots of small, natural and skier triggered releases were observed and reported by inbounds riders yesterday.
User avatar
JBella
 
Posts: 668
Joined: Wed Dec 14, 2011 9:19 pm
Location: Usually somewhere between Mexico and Canada.

Re: Taos Region

Postby JBella » Wed Dec 05, 2018 7:31 pm

Lots of snow blowing around on the ridges today, westerly winds and spiraling, upwards movement lifting snow into the atmosphere, the kind of action that creates small clouds from moving snow. I had to work inbounds the past couple days so didn't get out to tour anywhere, but can say all the reports of small slides were pretty accurate, maybe even a bit understated. The West Basin chutes were all sluffed out top to bottom yesterday, looked like some patrollers got into High Somewhere today and layed down a couple nice tracks after skitching through the upper sections. Talking with a patroller and a couple people who have been skiing through the weekend storm the reactive layers are the Halloween storm snow and previous layers, some slides (including a controlled slide up to 6' deep in Nino's) ran to the ground, or close enough for grass and rocks to become exposed.

All the Finger Chutes and Peace sign are filled in but have that gnarly, risk-it-if-you-dare look to them. Obvious windslabs are present on Kachina, rolling waves and light-dark-light drifts are moving around like sand dunes, the snow is cold and air temps have been below freezing above 10k.
User avatar
JBella
 
Posts: 668
Joined: Wed Dec 14, 2011 9:19 pm
Location: Usually somewhere between Mexico and Canada.

Re: Taos Region

Postby JBella » Thu Dec 13, 2018 1:49 pm

Significant wind event yesterday and through this morning. Southwesterly winds were intermittently strong on Wheeler's northwest slopes and throughout the region after noon yesterday, transporting snow onto NW-NE aspects. After a lull in activity just after sunset it picked up again around 11 as snowfall became widespread. 3-5 inches fell and the winds decreased after 3am. Bitter cold wind chills today though ambient temps are hovering around freezing in the lower elevations and in the teens up high.

The past few days I've been digging around various sites and finding similar conditions an all aspects near and below treeline - before yesterday and last night's weather event snowpack depths ranged from 2 to 3.5' comprised of a mix of advanced-stage facets in the bottom half of the snowpack and light dry soft slabs in the upper half. On the west side of Wheeler isolated 1f windslabs were present yesterday. In some areas on SE-NW aspects around 11k there is also a brittle suncrust in the middle of the snowpack above a layer of compressed surface hoar. Column and compression tests have been showing easy failures within a 3-4" layer of 1.5-2.5mm irregular facets on the ground. Minimal propagation characteristics in the upper layers indicate seemingly strong bonds which may create an illusion of stability, as soon as these slabs are isolated they are collapsing into the depth hoar easily.

These are tricky conditions to navigate. Previously known instabilities are still present, now with a heavier load affecting the snowpack dynamics. Crowns of recent slides were spotted on Kachina's east side a few days ago, yesterday we could see where the debris had piled up near the bottom of the apron and the fracture lines had been drifted over and disappeared. Not a lot of natural avalanches or instabilities have been seen since the December 2nd event, it's tricky to designate a specific avalanche potential rating without more thorough analyses and information, my opinion based on my own observations is it's somewhere in the upper moderate level on most aspects near treeline, with isolated pockets of higher potential on West through East aspects near and above treeline (obvious starting zones) and isolated steep pitches on shaded and cold Northeast and East aspects below treeline. Any open slopes, convex rollovers, and terrain beneath cornices and other windloaded features should be approached with diligence and caution, if at all.
User avatar
JBella
 
Posts: 668
Joined: Wed Dec 14, 2011 9:19 pm
Location: Usually somewhere between Mexico and Canada.

Re: Taos Region

Postby JBella » Sat Dec 22, 2018 9:35 am

I've had a good week hiking around on Frazer Mountain and Wheeler's north ridge.

December 17th ~

https://www.youtube.com/watch?v=aFCiLShllbg&feature=youtu.be

Frazer Mountain approximately 11,700 feet, N80°E aspect, snowpack depth 80cm. Lurking instabilities within the lower layers were reacting with similar results in each test I did. Multiple compression tests failed CT21Q3 within 1.5-2mm irregular facets 30cm above the ground. Upper snowpack is showing strong bonds within each individual layer, though shears were clean and smooth at a couple different interfaces one of which was not readily apparent, each appeared to be surface hoar that grew during November and early December. Indications that deep slab instabilities will be present for the near future

IMG_0142.jpg
IMG_0142.jpg (140.71 KiB) Viewed 633 times


December 18th ~

Mild conditions, warm.

December 19th ~

Significant wind event. From Frazer to Pattison Peak sustained WSW winds 35mph gusts up to 55mph. Not much snow available for transport on Frazer or across the valley on Kachina, however Lake Fork, Sin Nombre and La Cal basin were getting hammered with moving snow visible along those ridgelines.

https://www.youtube.com/watch?v=ApvwjIpBySE

IMG_0420.jpg
IMG_0420.jpg (296.02 KiB) Viewed 633 times


IMG_0412.jpg
IMG_0412.jpg (278.25 KiB) Viewed 633 times
Last edited by JBella on Sun Dec 23, 2018 8:37 am, edited 2 times in total.
User avatar
JBella
 
Posts: 668
Joined: Wed Dec 14, 2011 9:19 pm
Location: Usually somewhere between Mexico and Canada.

Re: Taos Region

Postby Jasper » Sat Dec 22, 2018 1:36 pm

Nice observation and camera work jbella! The sheep video makes me miss home.

https://www.instagram.com/p/Brd57whgYAR/


I would like to ask why you reported a Q3 shear quality? It is hard to say without being there in person, but I would rate that as a Q2, or maybe, a Q1. That being said we have exhausted all options for shear quality. Consequently many observers and forecasters, including those who developed shear quality, now report fracture character. Fracture character is more informative and allows us to better forecast propagation propensity.

I would rate your compression test result as a Sudden Planer (SP) because the column popped off, it could also be a Sudden Collapse (SC) but I can't tell from your instagram post. As the Canadians say these are both 'pops and drops'

Fracture character video: https://vimeo.com/30996756

Fracture character paper: http://arc.lib.montana.edu/snow-science/objects/issw-2004-182-191.pdf

Shear quality paper: http://arc.lib.montana.edu/snow-science/objects/issw-2002-508-513.pdf

Definitions can also be found in SWAG: https://www.americanavalancheassociation.org/swag/

I am also going to take a moment to mention 'deep slab instabilities'. The Deep Persistent Slab Avalanche Problem is often reserved for when the persistent slab avalanche problem becomes deeply buried. Canadians define it as 180-200cm. Forecasters in the USA reserve it for depths that are typically to deep for human triggering. It is better to call the 80cm snowpack with basal facets and Sudden Planer test results as a Persistent Slab Problem.

The Danger Lesson: https://soundcloud.com/user-660921194/the-danger-lesson

All that being said, let's keep the dialogue rolling!
Go when the going is good.
Jasper
 
Posts: 64
Joined: Fri Mar 09, 2007 10:51 am
Location: Santa Fe

Re: Taos Region

Postby JBella » Sat Dec 22, 2018 4:02 pm

These types of reactions are rated Q3 because they were uneven and not continuous across the area where the collapse occurred, which you cannot see in the video obviously if you are suggesting to rate this as a sudden planar which it is not because it was within s several inches thick layer of loose unconsolidated snow. A sudden planar collapse would be one that slides smoothly and quickly off a consolidated surface. The type of collapse I observed and described could not be classified as Q1 or Q2. Sudden collapses are often rated as a Q3 I just didn't include the SC in the rating because it was not necessary given the other information. As far as the deep slab instability issue, although what I said was that these observations indicate such an issue will exist in the near future I do consider this a deep slab instability because there is a deep enough slab sitting above the obviously unstable layer to be considered as such, several storms ago when we were already seeing reactions at this particular layer I would have considered it more of an isolated persistent slab problem but now there are overlying, semi- hard slabs from early December and November that have accrued over time.

https://avalanche.state.co.us/forecasts ... tent-slab/
User avatar
JBella
 
Posts: 668
Joined: Wed Dec 14, 2011 9:19 pm
Location: Usually somewhere between Mexico and Canada.

Re: Taos Region

Postby Jasper » Sat Dec 22, 2018 10:14 pm

jbella,

I continue to disagree that this is a Q3.

A Q3 is defined in Snow, Weather and Avalanches: Observational Guidelines for Avalanche Programs in the U.S. (Greene and others, 2004) as:

"Shear surface is non-planer, uneven, irregular and rough. Shear fracture typically does not occur through the whole slab/weak layer interface being tested. After the weak layer fractures the slab moves little, or may not move at all, even on slopes steeper than 35 degrees."(31)

Your slab slide into the snow pit, your slope angle looks to be less than 35°, and shear fracture occurred through the whole slab/weak layer interface. Yes the shear surface was irregular, but there is more information denying the Q3 rating than supporting it. This is not a Q3.

A Q2 is defined in SWAG as:

'''Average' shear; shear surface appears mostly smooth, but slab does not slide as readily as Q1. Shear surface may have some small irregularities, but not as irregular as Q3. Shear fracture occurs throughout the whole slab/weak layer being tested. The entire slab typically does not slide into the snow pit."

Your slab slide into the snow pit. The shear surface is not mostly smooth. But yes small irregularities and a shear fracture throughout the slab/weak layer exist. Half of the information denies this as a Q2 and half of the information supports it. It could be a Q2.

A Q1 is defined in SWAG as:

"Unusually clean, planer, smooth, and fast shear surface; weak layer may collapse during fracture. The slab slides easily into the snow pit after weak layer fracture on slopes steeper than 35° and sometimes on slopes as gentle as 25°. Tests with thick, collapsible weak layers may exhibit rougher shear surface due to erosion of basal layers as the upper block slides off, but the initial fracture was still fast and mostly planer."

The shear surface was fast, the slab slid easily into the snow pit on a low angle slope, and the thick persistent weak layer resulted in a rougher shear surface as the slab slid off. Most all of the criteria was met for a Q1 shear quality. This is a Q1.

I will venture to ask a few questions. What does the shear quality data mean? How should it be used in decision making and forecasting?

Where have you seen SC rated as Q3?
Here Karl Birkeland (developer of shear quality) and Bruce Jamison (developer of fracture character) compare the two systems and relate SC and SP to Q1.
https://avalanche.org/wp-content/uploads/2018/08/04_TAR_shearquality.pdf

In general the deep persistent slab problem is reserved for snow packs around 150cm or greater and potential for very large avalanches (D3 or greater) If you look at current avalanche forecasts for the United States you will find a deep persistent slab in the Northwest were snow depths are 150-180cm. https://avalanche.org

Remember words matter and the Conceptual Model for Avalanche Hazard enables a huge amount of information to be packed into an avalanche forecast with specific definitions. Yes there is potential for a deep persistent slab problem in Taos later in the year. Currently the problem is a persistent slab, as the weak layer is shallow enough to be triggered by a human, and the depth is unlikely to produce a D3. Treat and report the problem for what it is. This will enable you to increase the hazard and grow into a deep persistent slab problem if need be, as well as, not have to over forecast, backtrack, and potentially introduce hazard fatigue into the user group.

As I said before keep submitting the observations and keep the dialogue going. Maybe most importantly what does shear quality OR fracture character even tell us?
Go when the going is good.
Jasper
 
Posts: 64
Joined: Fri Mar 09, 2007 10:51 am
Location: Santa Fe

Re: Taos Region

Postby JBella » Sun Dec 23, 2018 8:35 am

It seems the distortion caused by my wide-angle lens may have fooled you ~ the slope angle in the one video I showed was 35° and transitions to 38° a few feet below where I was standing (and 25°a few feet above), it's the very top of the starting zone of an unnamed slide path, though actually closer to 11,300' not 11,700' as I misread my map. The columns I was getting reactions with weren't breaking and sliding into the snowpit so much as crumbling into the very loose and unconsolidated snow and falling towards the downhill side thanks to gravity, if you could see how the columns landed on their side which the camera didn't show that would be apparent, it's a humbling testament to how brittle and sketchy the snowpack here is currently. What was left of the incohesive and reactive layer was uneven and uncontinuous across the area where the columns had broken and fallen, which is why it is rated Q3, the collapse was sudden however there really isn't a clearly definable shear surface at a specific layer interface and this was the result in most of about a dozen column tests I did, including one on flat ground that didn't fall over for about 2 seconds after collapsing. I could have described this more thoroughly in my original post and I'll consider that when I relay obs in the future. Someone's classroom interpretations are fine but that's all they are, the snowpack won't conform how you want it to just to fit into someone's interpretive description or categorization, that is why guidelines including many in the links posted have been scrutinized and adjusted as long as people have been documenting snowpack observations. The current snowpack may not be as deep as you want it to be to be considered a deep slab by some Canadians' standards, and I was reluctant to use that description so early in the season however the characteristics are present ~ several storm slabs have now consolidated into a single, stiff slab above one specific deeply buried weakness close to the ground which has been present and known for 7 weeks. Though there are noticeable layers within the upper snowpack which can be separated with effort, they are together acting as a single slab due to bond strength within and between each layer. All the tests I've done along with what I know about the snowpack based on cumulative observations during each storm cycle and considering how the snowpack has evolved during and between each storm indicate it would be difficult to trigger the weak layer but if it is triggered it is possible the entire depth of the snowpack will move, leading to a relatively large and potentially destructive avalanche. Similar conditions are widespread everywhere I've been above about 11,000' on all but south aspects, many areas near and above treeline the snow is much deeper especially on windloaded slopes and crossloaded gullies. Since November there have been very few obvious signs of instabilities from the surface while moving, I've had to dig and really search to find any lurking instabilities during December.
User avatar
JBella
 
Posts: 668
Joined: Wed Dec 14, 2011 9:19 pm
Location: Usually somewhere between Mexico and Canada.

Re: Taos Region

Postby Jasper » Sun Dec 23, 2018 9:08 pm

Let us agree to disagree on the shear quality. I encourage you to use fracture character rather than shear quality. Fracture character is more informative and leaves less room for interpretation.

Yes, scrutiny is common when it comes to evaluating a snowpack, as well as in the research that produces guidelines for our industry.

What is the Taos persistent weak layer's sensitivity to triggers? What is the potential destructive size?
Go when the going is good.
Jasper
 
Posts: 64
Joined: Fri Mar 09, 2007 10:51 am
Location: Santa Fe

Re: Taos Region

Postby JBella » Sun Dec 30, 2018 11:47 pm

Some recent edits. Some places the snow is thin, others it's deeper than any of us are tall. Every storm is helping fill in the rocky areas. Feels like tomorrow's storm will be as good as predicted.

December 26th ~ https://www.youtube.com/watch?v=YkFW5V67ocg

December 27h ~ https://www.youtube.com/watch?v=T5crSX1Plu8
User avatar
JBella
 
Posts: 668
Joined: Wed Dec 14, 2011 9:19 pm
Location: Usually somewhere between Mexico and Canada.

Re: Taos Region

Postby JBella » Thu Jan 03, 2019 4:07 pm

The recent storm cycle has ended, with decent snowfall totals above 9k.

December 26-27 8-14"

December 31-January 2 14-22"

By early morning January 2nd, 14-22" had accumulated in the Wheeler Peak Wilderness. Mid-storm January 1st we toured to the Hidden Chute. Snow became deeper as we approached William's Lake, first signs of windloading appeared just below the second meadow. Snow continued to fall as we followed the Wheeler Peak Summit trail and switched back to the north just before the trail continues into the NW slide gully, then continued up towards the west-facing rock field where conditions got interesting. We made some switchbacks along the edge of the forest, stopped for a moment so my partner could repair a broken pole, then traversed onto and across the rock field where winds were blowing hard from the SSW, scouring the west aspects and depositing snow on NW aspects. Confident that we were not exposed to avalanche danger due to low slope angles and exposed rocks creating anchors all across the area, we contoured around towards treeline onto a NW slope where we encountered fresh 4F windslabs up to 45" deep, every one of these crossloaded drifts collapsed with that eerie whumphing sound as we stepped onto them. Then accross the far north side of this open area where the rocks taper out, the slope angle increased to about 33° and we didn't want to climb very far onto that slope so contoured quickly down and across to the trees. A few short and steep pitches up through some drifts among tree islands and we were at the top of an amazing run down through knee-deep powder in the Hidden Chute, with barely enough pitch to ride across the flats back to the trail. All in all a great tour, and important knowledge gained about the new storm snow and how it's reacting with the older snowpack. Those NW, crossloaded drifts are going to be an issue for some time.

January 1st Williams Lake Trail Snow.jpg
January 1st Williams Lake Trail Snow.jpg (298.76 KiB) Viewed 528 times


January 1st Williams Lake Trail.jpg
January 1st Williams Lake Trail.jpg (283.79 KiB) Viewed 528 times


https://www.youtube.com/watch?v=kW6ZGR-fcQI

January 2nd I spent some time inbounds to get some views and see what the area looks like. The sun was lighting up the mountains and riding conditions were decent.

https://www.youtube.com/watch?v=NOADeXy2Cr0&feature=youtu.be

The crossloaded drifts on Wheeler's northwest slopes were deposited by moderate to strong southerly winds as the storm began pulling out from the mountains the day before. Similar windloaded slabs have accumulated on northwest sides of terrain features in the starting zones at the top of the Peace Chute and Fingers, while west and southwest sides of these features are scoured down to rocks and older, harder snow. Overall the snowpack is still thin below treeline, however there are areas where it is much deeper ~ my 9'3" probe would not reach the ground where some of the drifts we encountered were at their high points.

January 2nd Wheeler Peak.jpg
January 2nd Wheeler Peak.jpg (307.74 KiB) Viewed 528 times
User avatar
JBella
 
Posts: 668
Joined: Wed Dec 14, 2011 9:19 pm
Location: Usually somewhere between Mexico and Canada.

Re: Taos Region

Postby Bob » Fri Jan 04, 2019 7:38 am

Marc linked this video in the Education section, but I think it's pretty relevant to Taos conditions. Note that the date it was taken was 12/8/18:
Marc wrote:Folks asking me about the conditions in the Taos area, here's a video that pretty much sums it up. I'd say she did a pretty good job on her first round. The slope wasn't even 30 degrees...for a reason. Other reports of AS triggered avis are out and about. Take care out there.

https://www.youtube.com/watch?v=pFgg2Az8KLM


There are a lot of reasons to be extra careful this season.
User avatar
Bob
 
Posts: 535
Joined: Tue Jan 16, 2007 12:10 am
Location: Santa Fe

Re: Taos Region

Postby Kerry » Sun Jan 06, 2019 10:28 pm

Skinned into Wildy Bowl to investigate the 12/7 and 12/1 layers that had shown easy potential for propagation during our mid-Dec L1 class. At the pit site, bottom of Wildy, at treeline, NW aspect (isolated hill on predominantly NE-E slope), 10,930', I assessed the 12/1 layer to be on top of 30-cm. The 12/1 layer still shows significant potential for propagation (PST 35/105 END and repeatable Sudden Collapse in Compression Tests). Although the snowpack is weak, has deep boot pen, it is cohesive enough for a soft slab. I exited Wildy Bowl toward skier's right of El Funko. Don't recommend this terrain due to potential for propagation and coverage is minimal for the amount of dead/down timber below Wildy. Didn't observe any recent avalanches, but vis was poor.
Attachments
Wildy Bowl-06-Jan.jpg
Wildy Bowl-06-Jan.jpg (173.75 KiB) Viewed 452 times
Kerry
 
Posts: 272
Joined: Fri Mar 16, 2007 5:17 am
Location: Albuquerque

Re: Taos Region

Postby Marc » Sun Jan 06, 2019 11:19 pm

Really nice profile, Kerry. This is congruent with everything that has been observed since early Dec., and appears to be continuing and not going away anytime soon. Granted, some folks have dropped some pretty serious lines, but are taking an apparent increased risk...for whatever reason. Certainly, if one gets lose underfoot, it could be a problem. I hope everyone who is traveling in the BC is taking a look at the NNMAE conditions being reported. @JBELLA has a really awesome thread on tracking the snowpack here, and it's highly appreciated. The fact that there's been 3x AS in Nambe, slabs have been released in bounds and out of bounds, and the roachy depth hoar layer resides across the region (and appears to be growing) is a testament to the overall conditions in the Sangres as of this date. Mod-high winds persist and loading on lee surfaces will also continue until the winds recede in the next couple of days...leaving behind many puffy zones (lee and cross loaded) with junkyard dogs laying in wait. Any bridging from previous melt-freeze crusts are being cannibalized, as is noted by your profile, and may present more objective hazards than avalanches alone. I'm trying a non-technical approach.
Marc
 
Posts: 29
Joined: Sat Dec 15, 2007 8:57 am
Location: New Mexico

Re: Taos Region

Postby Marc » Tue Jan 08, 2019 9:50 pm

More bad news from Taos Ski Valley. We did the deed and dug a pit to come up with a few tests that appear to be representative of the entire area on all aspect below and at treeline.
https://youtu.be/h7ofxXFG1wI
Looks like a D3 wind slab cut loose from the backside of Kachina into Wildy Bowl with this past storm cycle, but we also saw some point release slides under the cliffs that got early morning light that enacted some D2 wet slabs that were likely in the low R1-2 range. It got up to 3C today and there was loads of UV gain with the high solar index.
We targeted the junk yard dog at the 30 cm layer with the PST and it looks like if someone triggered something it could be quite large.The tests have been quite consistent, so good time to stay on low angle terrain and enjoy a tour. A couple above us also dug a pit and had similar results. Kerry will have a pit profile that should be quite informative as well.
Last edited by Marc on Tue Jan 08, 2019 10:07 pm, edited 1 time in total.
Marc
 
Posts: 29
Joined: Sat Dec 15, 2007 8:57 am
Location: New Mexico

PreviousNext

Return to Northern New Mexico 2018-2019 Conditions

Who is online

Users browsing this forum: No registered users and 1 guest