Phantom avy info? 04/06/11

Thanks for sharing your stories Marcus and Dan. Powerful reminders about the need to communicate about intentions and conditions before and actively during the trip. And even when others in your party have more experience and are the acting leaders to still keep thinking and assessing and be willing to share your thoughts.

Kudos to all involved with rescue ops.

Thanks for sharing your experiences, guys. Sharing your stories here has humbled me and undoubtedly "refreshed" my active awareness when in the backcountry.

I am grateful that all of you will live to ski another day....

Some more photos (all taken by Andy Hill - SPART and Alpental/Cascade Backcountry Ski Patrol).  I'll have a write-up on the extrication later today, as well as more thoughts on decisions/mistakes, etc.

The crown and area immediately above Dan's tree:


The climber's right flank:


Closer picture of the crown -- if memory serves, Dan an I were standing right below the cluster of trees on the far right of the frame.  The crown broke maybe a foot or two above my skis:


The crown at its thickest -- estimated 62 cm according to Andy:


Looking downslope from the crown:


The large tree on which Dan broke his femur.  I can only assume that, since I was right next to Dan, I threaded the needle on either the left or the right side of this tree:

Really glad you're all going to be OK. Thanks so much for sharing.

Thanks also for posting the pics - they really make it seem like the ultimate trigger was probably a wind slab sitting in that little bowl to the lee of the rock tower near the summit. I think I've met that slab before, but it was always smaller and pretty benign (at least when I was there, but things clearly can change).

Having that impression also makes this accident seem like it came out of a familiar scenario for a lot of us - looking for the goods just after a storm on familiar terrain, and wondering how aggressive you can go and still be safe. Is that a fair assessment? It just seems to make the accident a lot more relevant than the scary stories we've heard lately of 15 foot crowns running on a PWL. I get the sense that the decisions being made are ones we'll all encounter again, unless we decide to swear off skiing fresh snow and slopes steeper than 20 degrees. That is definitely one strategy that some folks employ. But for those of us who are still going to try and find the powder on some days ( and not every day is the right day to be out) then I think this is a pretty instructive read. Thanks for sharing.

Thank you Dan and Marcus for posting. Dan spoke to his thoughts approaching the final switchbacks, which reminds me to make sure my inner monologue in the backcountry becomes the outer dialogue with my partners.

Heal well!

I'm not passing judgement because I'm not familiar with that area, but from the pictures that slope scares the hell out of me. It seems awfully large and steep with way too many trees on it for me to feel safe after 2 feet of snowfall. Do people routinely ski that slope after heavy snowfall? Is it not as steep as the photos make it seem? And is that Alpental way down there at the bottom in that one pic? It seems that the three party members that were caught and carried are very lucky to have survived. I know everyone has their own level of risk tolerance, I'm just trying to wrap my head around this incident.

I'm glad everyone survived but until I learn more about Roger's injuries I'll refrain from saying glad everyone is ok. Dan mentions that he thinks will Roger will spend several months in a wheel chair - I'm really sorry to hear that.

From what I've seen a broken leg tends be a less complicated injury compared to a knee injury.

Was Roger skiing on the Fritschis? There was mention of a Fritschi binding that broke off at its toe piece.

A broken femur is a very serious injury, potentially life threatening, due to the possibility of cutting the femoral artery, painful, and necessitating a traction splint rather than a normal splint.

I'm so glad everyone is okay. Dan thanks for your account. I've always been very careful on that last little bit, thinking one day I would see it go. Like many people here, the Phantom has always been a backup plan when conditions get sketchy. That upper portion was usually avoided and laps in the trees, being careful to hang skiers right from the creek. Dan and Roger are both solid athletes and their recovery will be swift and forgotten. I can't imagine either of them will ever stop climbing, skiing or paddling just because of one epic. I too have been injured after a fall, having broken my talus bone in the Spring during a Tumwater adventure climb. Back then I took full advantage of my down time, spending time with my guitar and hitting music festivals in a cast all summer. Don't let it get you down, as this is really just an opportunity to catch up on other things you've been ignoring from this epic winter.

Aaron, yes that particular slope is fairly steep 35 plus degrees and people do routinely ski it. It has remained one of the more popular routes and is still one of my favorites. I find it deceiving because it would have to appear bad from the car or the couch for me not to give it a look so many of us go and see how conditions are in the trees for thousand feet or so before deciding it was dangerous and turning back. The deceiving part for me comes when you reach treeline. Then you are right about the toe of what they described as the deposit of their slide. When I am solo and there is that much new snow, I would probably ski down from treeline and enjoy a good tree skiing tour if I hadn't seen signs to turn me back before then. However, since it is a popular tour, one will typically find the skin track continuing up to the slot or the summit and it is tempting to continue on. This is also about the elevation that the snow pack will often change significantly from what was found in the trees. Not only is the temperature due to elevation enough of a change but it is exposed to more sun and wind and less anchors. One has to disregard what they saw in the trees and begin to evaluate it almost as a new mountain past this point and I can recall occasions that I have continued on with probably less regard than I should have perhaps because the skin track did also, or because we were in a happy place as a group and looking forward to a more full tour. I think as you get up toward the slot entrance, or actually just a little bit below it the wind slabs can throw another concern in that would not have been revealed by testing the snow earlier. I apologize if this appears as judging, it isn't meant to be. I just figured that I have seen the usual suspects on this tour for for quite awhile now and thought I would try to share what might be a typical thought pattern for some of us who could have easily made a similar error with those that might not be familiar with the tour.

Boy, Dan, that was a terrific write up and it is great of both you and Marcus to share your thoughts on this incident.

The photos show a very well-defined crown - broader than I imagined. Dan, you said that there was a noticeable layer below the new snow.

There was a slightly crusty layer about 12”-18” down representing the surface from the weekend.

And I understand that you evaluated the snow stability by feel and paying attention at switchbacks (which is normal with soft, new snow instabilities). You also said that your skiis didn't slip while climbing (which is a good guage of bond in most cases). I only have one question on this part of the situation: Did the slab fail at the crust or within an inch or two of the crust? Or did it fail in new snow wind density changes within the new snow?

Gary, these are Andy Hill's pit results, which he shared with me Thursday morning:

Avalanche Observation:
    4/6/11 – estimated occurrence at 09:30, observation at 16:00
    Mt Snoqualmie - Upper Phantom
    5,800 feet elevation, South Aspect, 30-35 degree slope angle
    Soft Slab Avalanche,
    Artificial Skier Triggered (unintentional),
    D2 force (bury/injure person),
    R4 Path Size (Large relative to how far it could have gone),
    I Bed Surface (release within new/old snow interface)
    Dry Snow Slab
    Avalanche Dimensions:
        40 – 62cm crown height
        50-75 ft crown width
        1,000+ ft vertical fall
        1,000+ ft path length

Snow properties (at Crown)
    Density of Slab (40-62 cm): Fist (dry)
    Density of bed surface: Finger/Pencil (wet)
    Shear Test: STE  (fails with min pressure)
    Shear Quality: Q1 (unusually clean, smooth, and fast)
    Compression Test CT10 (easy)
    Propagation Saw Test: End (on weak layer cut, slab slides to end)

EDIT -- I'd add that, as Andy observes, it failed at the old/new interface, but that it didn't go all the way down to the saturated crust from the earlier warm/rain events. That was another 18-24" down, I think, though I wasn't digging around up by the crown. I'll ping him and see if he has anything to add here.

Thanks, Marcus. I realize that for you analyzing this accident isn't academic, so I will keep my thoughts brief.

What jumped out at me was how even and well-defined the crown was. The second photo especially shows this. It obviously failed at the crust (or near it on slightly faceted snow - not in this case) which is what Andy found. It is interesting that at the time Andy investigated this he found the bed surface wet. That may not have been the case at the time of the accident, but failures often occur at a wet/dry interface. So, maybe radiation had penetrated to that depth during the day and after the accident. The telemetry shows it had been mid-20's and snowing for two days prior (not much sun).

A couple of additional useful tests for shallow instabilities (and this is not for you but others with less experience) are 1) to lift the uphill ski above a traversing track and try to slice the snow that is undercut by the track, 2) hand shear blocks.

Just reflecting how nice it is to consider the snow science of this. When I first got the call-out, I immediately thought we had another recovery. It's been a grim year in and out of bounds lately. My sharpest memory is coming up to Marcus and his group was to find everyone lucid with full recall of the events and smiling to see us. Couldn't ask for a better greeeting.

Once we got the litters moving, I moved up to the starting zone to figure out what happened. Didn't like hanging out there long (saw 200 feet of snow above w/o any legs left to hold it up), so my assessment was hasty. In retrospect, wish I took just a few more minutes as it's as much a mystery as it's obvious why it avalanched.

The mystery to me is how such low density snow (essentially powder) stayed together in a slab to pull out such a large pocket in that glade. If it was uniformly powder, it would have been a surface sluff and possibly just taken Roger down. To answer the question posed, the slide was the last 2-3 days of new snow on top of the rain crust from last week. From shear test alone, it was obvious there was no bonding between the crust and the new snow. That doesn't make it slide though. For a slab release like this, the top layer has to stay together and be lubed by something between it and the rain crust. My guess, some surface hoar/faceting formed up over that crust to give the slab something to slide on. Could have figured it out with more time and an eye glass. So, what kept that powdered layer together. If you look at the picture looking down the slide path, you'll see the refrigerator sized blocks of the slab from the starting zone. These stayed together and I think caused the propagation along the starting zone.

Talked with a few Alpental patrollers yesterday on the hill and went through the pictures. They were pounding the hill most of the day Wednesday and were pretty familiar with the conditions. With the benefit of some time and reflection, I'm thinking the true depth of the precipitation snow was the 40cm crown. My guess is the additional 22cm at the highest crown depth was due to the higher density wind transported snow that capped/enclosed the new snow. If I spent more time looking over that layer, I think I would have found 4 finger/finger density in to top (you can kinda see it in the picture). It created the top glue to keep it all together and allow Roger to leverage the slab to fail above him which was right at the apex of the slope convex.

Having said all this, I'm reminded that Gary Brill was my first avy instructor over 10 years ago. It's not surprising with our small community that he's also on this thread. Hope I did him proud....

My last thoughts on the matter is how close to home this hits. Marcus and I have taken the same avy classes together and performed the same pre-season training for several years. I consider him more methodical them me. I'm a phantom lapper and use that slope for exercise through the season. I've been up that glade a dozen times/season. I escorted Drew and Doug down the hill and felt pretty on par with their downhill skills. And, I'd put myself at about similar fitness to the entire group. From reading their accounts, I think I might be less risk averse in the snow. This easily could have been me in that group. It gives me pause.

Aaron, yes that particular slope is fairly steep 35 plus degrees and people do routinely ski it. It has remained one of the more popular routes and is still one of my favorites. I find it deceiving because it would have to appear bad from the car or the couch for me not to give it a look so many of us go and see how conditions are in the trees for thousand feet or so before deciding it was dangerous and turning back. The deceiving part for me comes when you reach treeline. Then you are right about the toe of what they described as the deposit of their slide. When I am solo and there is that much new snow, I would probably ski down from treeline and enjoy a good tree skiing tour if I hadn't seen signs to turn me back before then. However, since it is a popular tour, one will typically find the skin track continuing up to the slot or the summit and it is tempting to continue on. This is also about the elevation that the snow pack will often change significantly from what was found in the trees. Not only is the temperature due to elevation enough of a change but it is exposed to more sun and wind and less anchors. One has to disregard what they saw in the trees and begin to evaluate it almost as a new mountain past this point and I can recall occasions that I have continued on with probably less regard than I should have perhaps because the skin track did also, or because we were in a happy place as a group and looking forward to a more full tour. I think as you get up toward the slot entrance, or actually just a little bit below it the wind slabs can throw another concern in that would not have been revealed by testing the snow earlier. I apologize if this appears as judging, it isn't meant to be. I just figured that I have seen the usual suspects on this tour for for quite awhile now and thought I would try to share what might be a typical thought pattern for some of us who could have easily made a similar error with those that might not be familiar with the tour.

Thanks for more info about the slope Ron. If you stay low in the trees are you still exposed to hazard from above? Doesn't that slope slide full path sometimes, from near the top of Snoqualmie?

Thanks for more info about the slope Ron. If you stay low in the trees are you still exposed to hazard from above? Doesn't that slope slide full path sometimes, from near the top of Snoqualmie?

The phantom itself does, but folks usually climb up through the forest to climber's left. From what I recall, it's mostly old growth, suggesting it hasn't slid in a long time (and there is a bench between the thick forest and the open upper slopes). It doesn't seem an unreasonable proposition to climb the first 2000ft in the woods on high hazard days.

The phantom itself does, but folks usually climb up through the forest to climber's left. From what I recall, it's mostly old growth, suggesting it hasn't slid in a long time (and there is a bench between the thick forest and the open upper slopes). It doesn't seem an unreasonable proposition to climb the first 2000ft in the woods on high hazard days.

Thanks, this is very helpful in understanding the terrain.

Thanks for telling your side of the story, Dan. The photos and avalanche/snow data are very informative too, Marcus & Andy.

For reference, here is the Alpental telemetry for the days preceding the avalanche, extending back to the 8" of precip which fell in 65 hours at the end of March:
[size=small]
Northwest Weather and Avalanche Center
Alpental Ski Area, Washington

Wind sensors unheated and may rime

MM/DD Hour  Temp  Temp  Temp    RH    RH  Wind  Wind  Wind  Hour Total  24Hr Total
       PST     F     F     F     %     %   Avg   Max  Dir. Prec. Prec.  Snow  Snow
           5400' 4300' 3120' 3120' 5400' 5530' 5530' 5530' 3120' 3120' 3120' 3120'

---

3 28  2200    26    30    33    98    98    11    16   195     0   .03     0   98
3 28  2300    26    30    33    99    98     9    16   190   .01   .04     0   98
3 29     0    26    30    33    99    99     8    15   140   .02   .06     0   98
3 29   100    25    30    33    99    98    10    14   155   .04    .1     0   97
3 29   200    25    30    32   100    99    11    20   175   .04   .14     0   98
3 29   300    26    29    33   100    99    12    31   193   .05   .19     0   99
3 29   400          29    32   100                           .04   .23     2   99

---

3 29   500    26    29    32   100    98    16    33   206   .06   .06     2  100
3 29   600    27    29    32   100    98    18    34   233   .05   .11     2  100
3 29   700    28    29    33   100    98    17    36   232   .06   .17     3  100
3 29   800    29    30    34    97    99    18    37   239   .07   .24     3  101
3 29   900    31    32    34    95    97    18    32   244   .03   .27     3  101
3 29  1000    31    32    36    92    96    14    42   226   .04   .31     3  101
3 29  1100    30    33    38    91    94    14    34   221   .03   .34     3  100
3 29  1200    32    33    38    95    93    16    43   221   .03   .37     2  100
3 29  1300    29    32    37    95    97     2    16   221   .05   .42     2  100
3 29  1400    31    32    38    97    95     0     0   221   .04   .46     2   99
3 29  1500    29    33    38    95    98     0     0   222   .04    .5     2   99
3 29  1600    30    32    38    96    94     0     0   222   .03   .53     2   99
3 29  1700    30    32    35    96    96     0     0   221   .05   .58     2   99
3 29  1800    28    32    33    98    98     0     0   221   .04   .62     2   99
3 29  1900    28    32    33    99   100     0     0   222   .05   .67     1   99
3 29  2000    28    32    33   100   100     0     0   221   .06   .73     2  100
3 29  2100    28    32    33   100   100     0     0   222   .07    .8     2   99
3 29  2200    29    32    33   100   100     0     0   221   .09   .89     2  100
3 29  2300    30    33    33   100   100     0     0   222   .09   .98     2  100
3 30     0    31    33    34   100   100     0     0   222   .11  1.09     2  100
3 30   100    31    33    34   100   100     0     0   221   .19  1.28     2  100
3 30   200          33    33   100                           .29  1.57     2  100
3 30   300          33    33   100                           .36  1.93     2  100
3 30   400          34    33   100                           .14  2.07     2   99

---

3 30   500          35    34   100                           .31   .31     2  100
3 30   600          35    34   100                           .24   .55     2  100
3 30   700          35    35   100                            .4   .95     2   99
3 30   800          34    34   100                           .33  1.28     0   99
3 30   900          33    34    99                           .26  1.54     0  100
3 30  1000          33    35   100                           .18  1.72     0   99
3 30  1100    31    33    35    99   100     0     0   220   .14  1.86     0   99
3 30  1200    31    33    36    99   100     0     0   222   .15  2.01     0   99
3 30  1300    31    33    36    98   100     0     0   222   .14  2.15     0   99
3 30  1400    31    33    36    99   100     0     0   220   .14  2.29     0   99
3 30  1500    31    33    36    99   100     0     0   221   .14  2.43     0   99
3 30  1600    31    33    35    99   100     0     0   221   .12  2.55     0   99
3 30  1700    31    33    35    99   100     0     0   220   .17  2.72     0   99
3 30  1800    31    34    35   100   100     0     0   222   .09  2.81     0   99
3 30  1900    32    35    36   100   100     0     0   221   .11  2.92    -0   99
3 30  2000    32    36    37   100   100     0     0   223   .13  3.05     0   99
3 30  2100    32    36    36   100   100    16    36   249   .22  3.27     0   99
3 30  2200    34    37    36   100   100    26    48   232   .05  3.32     0   99
3 30  2300    35    36    37   100   100    33    63   235   .06  3.38    -0   99
3 31     0    36    39    38   100   100    35    56   239   .07  3.45     0   99
3 31   100    36    40    40   100   100    35    69   239   .07  3.52    -0   99
3 31   200    37    40    43   100   100    39    77   242   .13  3.65     0   99
3 31   300    36    39    43    96   100    49    89   243    .1  3.75    -0   98
3 31   400    36    39    42    97   100    40    75   243   .24  3.99    -0   98

---

3 31   500    35    38    41    98   100    41    80   247   .23   .23    -0   99
3 31   600    33    37    39    99   100    32    59   241   .32   .55    -0   98
3 31   700    32    35    37    99   100    34    63   243   .31   .86    -0   98
3 31   800    32    35    35    99   100    25    50   236   .19  1.05    -0   98
3 31   900    32    34    34   100   100     3    29   234   .24  1.29    -0   97
3 31  1000    31    34    34    99   100     0     0   235   .26  1.55     0   98
3 31  1100    32    34    35   100   100    13    55   236   .13  1.68     0   98
3 31  1200    32    35    37    99   100    23    47   239   .03  1.71     0   98
3 31  1300    32    35    38    99   100    24    44   238   .06  1.77     0   98
3 31  1400    31    35    39    98   100    29    53   249   .02  1.79    -0   98
3 31  1500    32    35    39    99   100    31    60   248   .03  1.82    -0   98  storm total: 8.1" in 65 hours
3 31  1600    32    35    39    98   100    26    49   241     0  1.82    -0   98
3 31  1700    31    35    39    94   100    26    45   243     0  1.82    -0   98
3 31  1800    31    35    38    96   100    27    41   257     0  1.82    -0   98
3 31  1900    30    34    37    98   100    24    37   255   .01  1.83    -0   98
3 31  2000    30    34    38    94   100    25    44   241     0  1.83    -0   97
3 31  2100    30    34    36    99   100    22    36   260     0  1.83    -0   97
3 31  2200    30    33    35   100   100    20    30   268     0  1.83    -0   98
3 31  2300    28    33    35   100    99    19    33   291     0  1.83    -0   98
4 1     0    28    33    33   100   100    15    21   292     0  1.83     0   98
4 1   100    27    32    32    99   100    13    24   291     0  1.83     0   98
4 1   200    27    32    33   100    97    16    21   292     0  1.83     0   98
4 1   300    27    33    34   100    93    16    27   292     0  1.83     0   98
4 1   400    28    33    34    99    96    17    26   292     0  1.83     0   97

---

4 1   500    27    32    34   100   100    19    28   292     0     0     0   98
4 1   600    28    32    34   100    99    12    20   291     0     0     0   98
4 1   700    29    33    35    99    97    15    28   292     0     0     0   97
4 1   800    30    32    35    98    99    15    26   292   .01   .01     0   97
4 1   900    31    32    36    98    99    16    28   275   .02   .03     0   97
4 1  1000    31    32    36    99    98    19    32   226   .06   .09    -0   97
4 1  1100    33    33    37    99    98    20    31   220   .07   .16    -0   97
4 1  1200    34    33    38    98    99    22    36   224   .06   .22    -0   97
4 1  1300    36    37    38    98    99    26    50   225   .02   .24    -0   97
4 1  1400    36    37    38    99    98    26    56   233   .07   .31     0   97
4 1  1500    36    39    39    99    99    25    50   231   .07   .38    -0   97
4 1  1600    36    38    41   100    99    24    45   226   .03   .41    -0   96
4 1  1700    35    38    40   100    99    24    52   236   .15   .56    -0   96
4 1  1800    32    36    38   100   100    22    43   247   .12   .68    -0   96
4 1  1900    31    34    36   100   100    14    38   268   .14   .82    -0   96
4 1  2000    31    33    35   100    99     0     0   272   .13   .95     0   96
4 1  2100    29    32    34    99    99     0     1   272    .1  1.05     0   96
4 1  2200    29    32    33    99   100     0     1   272   .07  1.12     0   96
4 1  2300    28    31    33   100   100     0     1   273   .04  1.16    -0   97
4 2     0    26    31    32   100    99     0     0   272   .04   1.2     0   97
4 2   100    24    30    32   100    98     0     0   271   .02  1.22     0   94
4 2   200    24    29    31   100    98     0     0   272   .02  1.24     0   97
4 2   300    23    29    31   100    97     0     0   272   .02  1.26     2   98
4 2   400    23    28    32    99    97     0     0   272   .01  1.27     2   98

---

4 2   500    23    27    30    99    97     0     0   271   .09   .09     4  100
4 2   600    22    28    30    99    98     0     0   271   .08   .17     0  102
4 2   700    23    27    31    99    98     0     0   273   .03    .2     1  102
4 2   800    24    27    31    98    98     3    28   267   .03   .23     0  101
4 2   900    23    27    32    96    97    21    36   238   .09   .32     2  102
4 2  1000    24    27    32    94    96    20    33   237   .07   .39     3  104
4 2  1100    28    28    34    91    97    21    41   236   .04   .43     5  105
4 2  1200    27    28    34    94    98    21    42   242   .01   .44     4  104
4 2  1300    26    29    34    93    97    22    34   248   .03   .47     5  104
4 2  1400    28    28    33    95    99    16    30   250   .07   .54     5   -4
4 2  1500    24    28    32    98    98    20    44   247   .13   .67     6  106
4 2  1600    24    28    33    97    98    22    44   270   .15   .82     8  108
4 2  1700    23    28    32    97    98    17    29   285   .13   .95     9  108
4 2  1800    23    28    31    98    98    22    37   257   .06  1.01    10  109
4 2  1900    22    28    31    99    98    18    33   276   .01  1.02    10  110  storm total: 2.3" in 36 hours
4 2  2000    22    28    31    97    97    15    31   290     0  1.02    10  110
4 2  2100    22    28    31    99    97    19    31   283     0  1.02    10  110
4 2  2200    22    27    30    99    98    20    34   261     0  1.02    10  110
4 2  2300    22    27    30    99    98    21    31   252     0  1.02    10  109
4 3     0    22    27    30    99    98    13    26   277     0  1.02    10  109
4 3   100    22    27    30    99    97    10    22   308     0  1.02     9  110
4 3   200    21    27    30    99    97    12    23   298     0  1.02    10  110
4 3   300    21    27    30    99    98    11    21   312     0  1.02     9  109
4 3   400    21    27    30    99    97    11    28   288     0  1.02     9  109

---

4 3   500    22    27    30    99    97     8    16   252     0     0     0  109
4 3   600    22    27    30    99    98     8    13   263     0     0     0  109
4 3   700    24    27    31    96    97     7    14   289     0     0     0  108
4 3   800    25    26    32    94    98     6    12   284     0     0    -0  108
4 3   900    27    28    35    88    97     4     9   254     0     0    -0  106
4 3  1000    30    28    36    84    98     3     6   240     0     0    -0  105
4 3  1100    33    29    37    84    98     2     6   245     0     0    -0  105
4 3  1200    32    30    37    86    98     3    12   224     0     0    -0  105
4 3  1300    34    30    37    86    93     6    13   240     0     0    -0  105
4 3  1400    34    30    37    87    93     6    14   240   .01   .01    -0  105
4 3  1500    33    30    36    92    95     7    13   237   .01   .02    -0  104
4 3  1600    32    30    35    91    95    10    18   238   .01   .03    -0  104
4 3  1700    27    29    34    97    96    12    18   234     0   .03    -0  104
4 3  1800    25    29    33    97    96    12    22   232     0   .03    -0  104
4 3  1900    24    29    33    98    97    10    16   228     0   .03     0  104
4 3  2000    24    28    32    99    97     8    18   223     0   .03    -0  104
4 3  2100    23    27    32    99    96     7    13   229   .01   .04     0  104
4 3  2200    23    27    32    98    97    12    26   235     0   .04     0  103
4 3  2300    23    27    32    98    97    16    28   244     0   .04     0  104
4 4     0    23    28    31    98    97    17    30   241     0   .04     0  103
4 4   100    23    28    32    98    98    18    39   238   .01   .05     0  104
4 4   200    24    28    32    99    97    19    31   229   .03   .08     0  105
4 4   300    24    28    32    99    97    18    28   231   .04   .12     0  105
4 4   400    24    28    32    99    97    18    27   233   .04   .16     1  105

---

4 4   500    24    28    32    99    97    20    36   234   .04   .04     1  105
4 4   600    25    29    32   100    98    24    37   234   .06    .1     2  106
4 4   700    27    29    32    99    97    21    34   237    .1    .2     2  106
4 4   800    28    30    33    98    97    20    33   234   .09   .29     3  107
4 4   900    28    31    34    96    97    19    33   238   .07   .36    -0  109
4 4  1000    29    31    35    92    96    15    27   238   .06   .42     0  109
4 4  1100    30    31    35    91    97    16    29   239   .06   .48     1  109
4 4  1200    31    31    36    90    96    14    30   229   .04   .52     1  109
4 4  1300    30    31    36    91    96    15    29   226   .05   .57     1  109
4 4  1400    29    31    35    94    97    19    38   226   .05   .62     1  109
4 4  1500    29    31    34    97    96    22    40   230   .03   .65     1  109
4 4  1600    29    31    34    97    97    18    40   227   .05    .7     1  109
4 4  1700    28    30    33    98    97    15    32   230   .05   .75     1  109
4 4  1800    27    29    33   100    98    20    37   220   .04   .79     1  108
4 4  1900    26    29    33    99    98    25    45   228   .04   .83     1  108
4 4  2000    26    29    32   100    98    27    42   239   .07    .9     1  108
4 4  2100    27    29    32   100    98    25    48   239   .06   .96     2  109
4 4  2200    26    29    32   100    98    25    44   241   .07  1.03     3  109
4 4  2300    25    29    33   100    97    30    58   251   .06  1.09     3  109
4 5     0    23    28    32    98    98    30    54   251   .02  1.11     3  109
4 5   100    23    27    32    96    97    23    45   254     0  1.11     3  109
4 5   200    23    26    31    98    96    23    45   253   .04  1.15     4  110
4 5   300    22    26    31    99    97    25    48   251   .03  1.18     4  109
4 5   400    22    26    31    95    97    20    38   243   .01  1.19     4  110

---

4 5   500    21    26    30    98    96    21    38   250   .05   .05     5  110
4 5   600    20    25    30    92    97    21    40   247   .02   .07     5  110
4 5   700    20    24    29    91    96    19    35   243   .02   .09     5  110
4 5   800    21    24    30    94    96    15    26   237   .07   .16     0  111
4 5   900    22    25    31    92    95    17    31   242   .05   .21    -0  110
4 5  1000    23    26    31    93    96    19    36   248   .03   .24     1  111
4 5  1100    24    26    33    90    93    17    33   249   .02   .26     1  110
4 5  1200    25    27    34    90    93    19    36   252   .01   .27     1  111
4 5  1300    27    28    35    91    96    15    27   248   .03    .3     2  110
4 5  1400    26    28    34    94    95    17    31   247   .03   .33     2  110
4 5  1500    25    28    34    88    97    19    36   246   .01   .34     2  112
4 5  1600    25    27    32    97    96    17    35   240   .06    .4     3  112
4 5  1700    23    27    32    96    98    19    40   245   .05   .45     5  113
4 5  1800    22    27    31    95    97    17    36   246   .03   .48     5  112
4 5  1900    23    27    30    98    96    10    21   240   .08   .56     5  114
4 5  2000    23    26    30    99    97     9    21   231   .07   .63     6  114
4 5  2100    22    26    31    99    97    10    17   236   .04   .67     7  116
4 5  2200    23    26    31    99    96    11    20   235   .04   .71     8  117
4 5  2300    23    26    31   100    97    13    25   230   .08   .79     9  117
4 6     0    23    26    31   100    97    13    29   233    .1   .89    10  119
4 6   100    23    26    31   100    96    13    34   240   .04   .93    11  119
4 6   200    22    26    30   100    97    11    28   241   .07     1    12  121
4 6   300    22    26    30    99    97    16    28   241   .01  1.01    11  120
4 6   400    21    25    30    99    97    13    27   240   .07  1.08    12  121

---

4 6   500    20    25    29    99    96    16    31   242   .02   .02    12  120
4 6   600    19    24    29    95    95    16    34   235   .01   .03    12  121
4 6   700    18    23    28    94    94    11    27   253   .04   .07     0  122  storm total: 2.5" in 55 hours
4 6   800    19    23    29    92    94    14    26   238     0   .07     0  122  season-to-date snowdepth maximum
4 6   900    22    25    32    84    95    12    26   247   .02   .09     0  120  avalanche at 930 PDT (830 PST)
4 6  1000    23    25    32    86    95    13    23   231     0   .09     0  119
4 6  1100    25    27    37    76    93    10    18   234   .01    .1    -0  119
4 6  1200    32    26    34    83    95     7    26   246   .02   .12     1  119
4 6  1300    25    25    31    92    93    12    28   243   .03   .15     1  119
4 6  1400    26    25    30    94    93    11    24   240   .06   .21     1  119
4 6  1500    31    26    34    83    94    10    23   230   .04   .25     3  120  rescue teams arrive
4 6  1600    26    27    32    84    96     8    16   240     0   .25     3  119
4 6  1700    25    26    32    88    96    15    33   232   .01   .26     3  120
4 6  1800    21    26    29    88    96     9    19   230     0   .26     3  119
4 6  1900    19    25    28    94    96    11    21   244   .01   .27     3  119
4 6  2000    19    24    27    95    95     9    18   322     0   .27     3  118  patients reach trailhead
4 6  2100    19    24    27    95    95     8    12   322     0   .27     2  118
4 6  2200    20    25    28    96    95     7    12   322   .02   .29     3  120
4 6  2300    19    24    28    97    95     8    18   322   .01    .3     3  119

(Note that times in the NWAC telemetry remain on PST year-round.)
[/size]

An observation which I just noticed in the telemetry (posted separately since the telemetry above used up the entire 20000 character limit):

The 122" snowdepth at 800 PST on April 6 (half-hour before the avalanche) is the seasonal maximum thus far at the Alpental site. Seasonal maxima were reached at several other NWAC sites in the WA Cascades at the same time, within +/- a couple of hours (Mt Baker, Stevens Pass at 4000, 4800, and 5240 ft, Paradise, etc). Given such a widespread regional maximum, the seasonal snowdepth maximum at the avalanche site (5800 ft) probably also occurred at that same time, just before the avalanche.

That is probably a very significant fact, is it not? Greater snowdepths produce less anchoring on this type of slope, as more and more of the protruding trees (of varying height) and larger rock outcrops are buried by the deepening snowpack. However, despite this obvious significance on certain types of slopes, total snowdepth appears to be largely ignored in the analysis of avalanche accidents.

It appears that the humidity differences between elevations may have had an influence.

Spring snowpack is really different from winter snowpack.

The effect of the longer days and strong diffused (especially through clouds) sunlight is underrated.

Marcus, Drew et al...I'm glad to hear you're all okay and were able to respond and care for yourselves promptly as well as keep high spirits through the day. Remarkable. Thanks also for your thoughtful reflections, very noble of you all.

Like many people here, the Phantom has always been a backup plan when conditions get sketchy.

Although I've never skied the upper sections of the Phantom I should hope this isn't true for most people.
There's a howitzer directly accross the way that we all ski by often that has fired that slope many times. In my opinion it's considerable avalanche terrain, even in the lower trees due to the slopes above and it's obvious ability to have a full slope run-out...

I wonder how much melting and seepage from the trees occured the days prior to the avalanche, creating several unstaple sliding points that allowed the crack and failure between them...

Marcus - what struck me from your story is that you guys actually stocked, carried, and knew how to use the safety gear and first aid to treat an injury. 

Amen to that. As one who has spent several hours on snow in waning light with a broken femur waiting for a sled ride, also in good company of people who knew what to do and did not lose their cool, I can't say enough about how good it was to have a puffy jacket or two, foam pads from packs, a light bivy sack, and a thermos with some hot sweet tea. Extra clothes and extra calories are essential first aid gear, for the injured and those who stay with the injured.
Really glad you guys came out of this with nothing worse. Thanks for sharing the story.

Was Roger skiing on the Fritschis?  There was mention of a Fritschi binding that broke off at its toe piece.

Hey cchapin,

The Fritchis in question were mine. Since I was in touring mode with my heel free, the leverage was huge on that toe pivot, and it just sheared the aluminum. Then the binding part came off my foot at some point I guess. That piece didn't turn up (though we didn't look that hard) even though that ski was right next to me at the tree when everything stopped.  The other ski was recovered farther down the hill, and its binding is mostly fine except the plastic toe piece is broken; not sure how that happened.

Roger was on BD Tele gear, non-releasable, which is the setup he vastly prefers and relentlessly promotes.    Unfortunately, in this case I think his bindings were a large contributing factor to his twisted knees.  The skis were eventually torn from his boots, but not before subjecting his legs to some serious torsional forces.

Dan

Regarding first aid gear, etc, we certainly could have used more. I had only half of my usual first aid/toolkit bag, which was thankfully enough when we scavenged Dan's harness and a bunch of Voile straps to make the traction splint. We would have been hard pressed to do another one with the gear we had, if I'd broken my leg too.

I usually have a SilTarp which I'd left behind -- that's never getting left behind again. We were able to keep Dan fairly warm with the one space blanket and the garbage bag liner from my pack, but Roger got the short end of the deal and was probably a little colder. Thankfully the weather wasn't too bad and we did what we could to build a snow wall around him to keep out the worst of the wind.

I also usually have some more robust painkillers, but did not at the time.

Re: bindings, I may have said already but I was on my NTN tele setup and they released from my feet without my noticing it. Not a hint of pain in my knees, thankfully, but I think I may have gone for a longer ride because my skis came off so quickly and didn't hang up on trees to slow me down.

Marcus, Drew, Dan: thank you so much for exposing yourselves by sharing your tale here. I'm certain that many will be helped. I think that, as touring practices change (b/c of the internet, guidebooks, improved gear, etc.), the type of trouble folks get into will also change. If we, as a community, self-report mishaps and close calls we can all keep a more accurate picture of the ways in which skiers are getting into trouble. That may help us ski more safely.

Here's hoping for a speedy recovery for Roger and Dan.

Best Wishes,
Micah Prange

My last thoughts on the matter is how close to home this hits.  Marcus and I have taken the same avy classes together and performed the same pre-season training for several years.  I consider him more methodical them me.  I'm a phantom lapper and use that slope for exercise through the season.  I've been up that glade a dozen times/season.    From reading their accounts, I think I might be less risk averse in the snow.   This easily could have been me in that group.  It gives me pause.

Thanks, Andy for the assessment. It is clear that there is much more to an accident than just snowpack (terrain, weather and group dynamics). The snowpack questions just help us to understand Why did this happen here? Marcus and Dan have given great insight into the other parts of the incident.

I think that all of us have been in situations where either we were uncomfortable  or where something did happen. When people are willing to share their experiences we can all learn.

Edited to add: Dan and Marcus's stories sure point out how difficult it is to extract oneself from a situation once it starts to evolve. It is not easy to make the decision to turn around.

We are pleased that everyone in your group made it a “round-trip”.  I imagine the tears of joy from your loved ones and the hours of replaying the day’s events might qualify you as a more cautious touring partner for future adventures. You can’t always control the unplanned events in your life but you can control how you react to those events.

Zap & Jill

When spring is trying to act like winter on those low elevation , potential sun- facing, soaking slopes (something happening in snowpack rapidly..solar heat?) with new fallen snow (and or wind transport/slab?) I get a little nervous..
Things happening rapidly in/to snow pack (heating?)...

Seen a slope go after it was fully skied out after everybody had left. The pillow immediately under the cornice--which a small part of, dropped onto pillow--had triggered and released the "pillow" and ultimately resulted in the whole slope being obliterated (2' appr.crown). The ski tracks came in from the side below the pillow. The sun was full on at the time of 1pm.. a few hours after the skiing/freshies were partaked...

I wonder what ski cutting immediately below that cornice would have produced early on that day...seems like a good idea..

My two cents worth..been in a slide my self in Crystal area years ago...don't want to do that again, but don't want to forget my thinking errors on that one ...I should not have been above a rock band and the terrain trap below that-- especially new cold snow, that it was rapidly warming/cooking in the sun...

Marcus: Great write up in your avalanche. I suspect there may be more thoughts that went through your mind while you were in the avalanche...some of us have been there.

Don/Dan. Love the photo of you smiling! Now that you are laid up, don't watch too much Jerry Springer.

Look forward to more of your skiing in the future!

thanks to all those involved for your honesty and openess with the community. this is extra valuable as most of us I assume know the area where the slide was triggered, and can focus on the other variables and learn something valuable from your experience.

speedy recovery to those injured and another shout out to SAR, great work everyone.