Friday, December 13, 2013

Slide

The snow pack let out a big, long, sigh.
I looked over at T2, and we exchanged wide-eyed expressions. The snow underfoot had just made one of the bigger collapses I’d ever seen, heard, or felt.
-
It was another sunny day in mid-April of 2013, and T1, T2, and I were all skinning up a wrap-around ridge that lead to the summit of Colorado Peak in Summit Pass (Peak 4539) in what I’ll refer to as “Mile-Wide Bowl,” two drainages west of the highway.
We approached by climbing Colorado’s main east rib, before shuffling across the flat skyline ridge, past the sub summit (Peak 4325), and onward to the entry of a couloir on the eastern corner of the MWB.
Climbing from the highway on Colorado’s express route east rib was solidified rock hard by wind and sun, as is typical for the aspect this time of year, and we had experienced a little collapsing on the thin, wind-effected snow on the open exapanse of the sky line ridge. We had also seen fractures on the sun-cooked south face as we cruised to the summit on the main ridge; but here, in the north-facing bowl, so far, the only issue we had was marginal snow.
A recent, moderate wind event had left behind a mosaic that ranged from unaffected recycled pow, to inch-thick breakable crust; while ridges were firm.
The Chugach National Forest avalanche advisory for Summit Pass warned of the folliwng primary concern;
“With several days of mostly clear skies, cold temperatures and almost a week since the last snowfall, the Summit Lake area mountains have recently only been accosted by wind. North and westerly winds picked up yesterday with plumes on the peaks (see photo below). Amazingly enough however, much of the terrain we found had escaped wind effect and the riding conditions were quite nice.
That said, keeping a close eye for cracking at the snow surface and areas with recent wind affect will be wise. Places most likely to get tangled with a wind slab will be in the upper elevation steep terrain. Quick hand pits, ski cuts and feeling for stiff snow over light snow with your pole are good techniques to use while traveling.”
 
We entered the bowl by skiing a zig-zag, rock-strewn couloir. It skied like garbage due to the breakable. When N1 ski cut the run, we jumped at the sight of what we thought was a fracture, but closer inspection revealed it was in fact a large, broken piece of harmless wind crust, perhaps an inch thick, sitting on the buried powder.
At the bottom of the run, even though the skiing sucked, we decided we were far enough back, and the MWB had so many options for a better day, that we would at least do recon and take pictures.
The MWB is sort of divided into an east and west half, with the conical summit of Colorado Peak cutting it roughly in half. We dropped down to the bottom of MWB, and climbed back up a wide gully to the far west that brought us into a small, intermediate basin, below and west of the summit. To the climber’s right was a steep slope punctuated with rock outcroppings, ahead was an open bowl run beneath the peak, and to the left was a wrap-around ridge that lead most the way to the summit.
We might have been content to snap some pictures and ski out of the intermediate basin via a short but steep couloir we had eyed earlier, when we heard T1 holler from the summit.
T1 started an hour and a half behind us with the plan to sync up, and had just reached the top. He dropped off the summit, and we were surprised to see him carve descent turns on the northwest-facing aspect.
Fully grouped, we decided that T1, T2, and I would head for the summit and farm T1’s tracks, while N1 wanted to boot the climber’s right face and ski the outcrops. We would have a visual on N1 the entire time, and vice versa, along with the ability to yell back and forth if needed; but N1 took a talkie for some extra assurance.
The wrap around ridge was the safest way to the summit by your standard textbook definition of safe travel in avalanche terrain: Isolated from the adjacent terrain, it lifted us first up and out of the intermediate basin, before climbing steeply to the summit.
The ridge, however, was firm – though not as bakes as the express route east rib –opposed to the powder-to-breakable snow found in the bowls and couloirs.
I clicked into my ski crampons, and headed upward on a vertically-inclined uptrack.
T1 and T2 cut their own skin track at a more moderate grade.
About 300 feet above the floor of the basin, we reached a point where the ridge subverted into the steep summit cone.
The snow was getting very firm now, but the grade was too steep for my ski crampons to hold any more.
T2 was about 20 feet behind me, and T1 about 20 feet further back from him. I turned around to T2 to say that I was thinking about kicking steps the rest of the way up to the summit.
He suggested we just push out into the bowl where we would find easier skinning in the softer snow.
Though your textbook would say this would open up our exposure, nothing indicated this latter option to be a bad decision as far as snow stability was concerned, and we agreed that would be a good plan and easier than booting.
I might have taken two steps when the snow collapsed.
-
For a second, it wasn’t clear if the snow would slide or not. The ground just seemed to tremble. It may have slid a bit, and even stopped for a fraction of a second, I don’t know.
Suddenly, the slope started a slow-motion disintegration into blocks.
Someone might have said “here we go,” and I saw T1 and T2 turn on their tails and start trying to ski on their skins with their risers up.
As the snow broke apart beneath us, I was still facing uphill, and my feet sank down about 6 inches to the bed surface where the crampons bit in.
Between the shaking and the biting in, I was easily knocked forward, first onto my knees, then hands, then sprawled out on my stomache.
I started sliding down; the ridge growing upward before me.
All the while I was trying to keep eyes on T1 and T2 as they fought awkwardly to stay upright.
What commenced was a sometimes strange, though very articulate internal dialog.
“Wrong role. You’re in this. Stop Watching T1 and T2.”
Blocks of snow anywhere from a few inches to 16 inches thick were jostling next to me. A few bounced against my head and face, momentarily smothering my breathing with dry powder.
“This is bad! You’re not supposed to be laying down!”
I could feel my hands and ski crampons scraping along the hard bed surface.
I flipped my poles upside down and began stabbing the handles at the bed surface as if I had a wippet, which I regretfully did not.
They would bite in a little bit, and I could force weight on them, but it was not enough to hold purchase, just act like plastic brakes on a child’s sled.
I kept at it. Over and over I would stab, hold, drag, release, and repeat.
I was able to start slowing down.
Blocks of snow began to pummel me in the face and slide by. I knew that strangely, it was a good sign, and I was moving slower than the surrounding snow
I felt like I was fighting, and that gave me some sense of hope and confidence.
My head was still on a swivel, gauging how far I had slid, what was going on below me, and where T1 and T2 were.
I saw that both of them were still fighting like hell to stay on their feet.
Undoubtedly they were trying to keep from going over the other side of the ridge down into the main basin. That slope, just out of my sight, was a veritable cheese grater of Chugach shark fins.
I could feel the snow trying to pull me off the other side of the ridge and back into the intermediate basin. I was less worried about rocks, but more worried about getting buried in the basin.
Thoughts continued to swirl through my head.
“This slide is 1.5 feet deep.”
“It’s not going very fast. It feels like it might stop any second, but it won’t. Why not?”
“Keep stabbing. You gotta stay on this ridge. Don’t go over the side!”
“T1 and T2 are fighting hard. They really can’t go over that other side!”
“Is my beacon on?”
“I think I could reach into my jacket and turn it on right now.”
“Are you fucking serious?”
“Why would it not be on? Have you ever skied with it off?”
“Dumb question! Focus!”
“I can’t believe I spent a week in the Alaska Range and I’m about to get killed back here.”
“FOCUS! Keep stabbing!”
As my head whipped up and down and around, I noticed there wasn’t as much snow moving above me anymore, but below me, chunks looked like they were piling up in the basin and starting to slide out across the floor toward the wide gully we climbed.
Meanwhile, I felt like I was losing my battle to keep from going into the intermediate basin.
Finally, I got too close, and felt the incredible pull of snow and gravity take over.
If I had any premonition that I had some kind of control, it was gone immediately.
The feeling wrenched the confidence I thought I had seconds ago right back and left a gaping hole filled with fear.
“If this slide runs through the intermediate basin, it could keep going down the gully we climbed up…this could get really bad.”
“This is starting to hurt.”
I was moving too fast to stab at the bed surface with any effectiveness, and accepting that I was going down to the bottom, I let go of my poles.
“Goodbye poles.”
“Will they still be here in the spring?”
Who cares?”
“Time to start thinking about taking deep breathes.”
“Cover your head, curl up, and get ready.”
“What is this going to feel like?”
“I’m scared.”
“It would be good if this would just stop now.”

Silence.

The slide stopped, leaving me 10-15 feet over the end of the ridge, and maybe 200 feet from where it all started, just out of sight of T1 and T2.
“Were they still fighting on the other side of the ridge?”
“SLIDE!” I yelled.
I really don’t have much in the way of a sense of time, but it had probably been about 15 seconds since the initial collapse. All three of us were so close together when the slope let go that not a word was exchanged.
In retrospect, yelling was kind of funny, but in my mind, I was worried that somehow N1 had not seen the incident and might still be able to spot T1 and T2 if they were still in the mix.
“I’m OK!” both T1 and T2 yelled.
T1 and T2 stayed on their feet and stayed on the ridge. Both of them came to a stop bit higher than me.
“Is everyone OK?” N1 yelled from across the way.
He had heard the initial settlement, and watched the whole thing from a stadium seat.
-
The initial collapse was a slab that fractured maybe 15-20 feet wide about 20 feet above T1 and I, about 6 inches deep. The shallow slab probably slipped, partially arrested, before triggering a deeper slab that released below us and went much wider to about 1.5 feet deep; hence the slow start. The width was hard to judge, but probably about 100 feet wide at its widest, though as narrow as 15 feet near the top, and the debris had run about 300 feet to the floor of the intermediate basin, piling in blocks to about three feet deep at the absolute deepest.
By all accounts, the slide was rather small.
Once the main body of the consolidated slab hit the flat basin and encountered the unconsolidated powder and breakable in the sheltered bowl, it ran out of energy and cohesiveness.
-
T1 and T2 traversed around the ridge to where I was. T2 stopped, and banged a newly exposed rock with his pole along the way. We were lucky none of us found any of its neighbors.
We reconfirmed that everyone was OK, and got on the radio with N1, who was preparing to make his drop to meet us down below. He had made it a comparable height up the other side.
N1 said later that from his perch, he knew within seconds that no one was at risk of deep or even full burial, but he was very worried about trauma, especially if anyone went over the cheese grater.
T2 announced this was a fine time to have lunch, and plopped down on a block of debris to dig out a juicy burger from his pack.
I dug down 8-10 inches below where I’d stopped and found my poles, shook the snow out of open pockets and the open side zips of my snow pants, and began to transition.
That was it, it was time to go home, we’d seen far more than we bargained for.


Looking down from where I stopped. My pocket was open and my camera lens was smeared with snow.
So what happened? Was this one of those, we ignored all the clues?
A lot of people involved in slides will report that everything told them to go home.
As we discussed the events, no one seemed strongly of that opinion.
We had seen tell-tale evidence of instability on the flat, wind-whipped sky line, and on the sun-cooked south side, but north-facing was fine – though lacking in quality.
The avalanche forecast had warned of wind slab issues, but wind slabs are a fact of life in the mountains, and something we deal with regularly.
From a terrain management perspective, we were also climbing the least exposed line, staying high and above the typical avalanche paths – in theory anyway. In retrospect, we would have actually been safer out in the bowl or booting a couloir where the snow was not slabbed.
That being said, I think we made some small errors that did not help us:

1. Long term impact from recent weather: Four weeks prior, in late March, a warm and windy storm rolled through that formed what would become a persistent and lousy base throughout Summit. A few days after “storm 2,” came in, depositing a descent snow fall, accompanied by more moderate winds than the previous storm, resulting in numerous naturals that I and others observed in north facing terrain throughout Summit Pass.
Smaller storms and a lack of wind was briefly able to rebury the persistent base without loading slopes enough t trigger the same number of widespread naturals through the early part of April.
In the past two weeks though, the snowpack had been subject to a prolonged and unseasonable warm and dry spell that formed crust into the high elevations, only recently covered by a light storm, earlier in the week prior to our slide. After this recent storm, clearing skies brought moderate west winds that created the variable snow quality in the bowl, and firmed up the slabs on the ridges.
It was a carbon copy of storm two back in March, in which a large number of naturals were triggered.
Adding to this, we were two drainages west of the highway, and though we had elevation on our side, the snowpack was notably thinner and drier here than it was in eastern Summit Pass. We were treating this snowpack much like we would have the snowpack on Ravens Ridge or Spiritwalker.

2. Aspect orientation: Though our ridge was in a north-facing bowl, it’s final pitch ran at north-south axis, allowing it’s west side to sit in the afternoon sun. Temperatures had swung back to the cool side in the last week, and were running from the low single digits to negative single digits at night, to high 20s during the day. The cold dry air was rotting out weaker snow under the newly formed slabs, and daytime warming was making for more reactive conditions later in the day, with the caveat that the major indicators were absent (i.e., even on south faces there were few natural rollers or pinwheels because of a gentle but steady northwest wind).
 
3. Our travel techniques were poor. I prefer more of an “SFU” approach when traveling on wind slab, as lateral traversing on a splitboard is tough on my ankles.  My crampons let me pull steeply up firm snow. T1 and T2 cut their own skin track at a much more reasonable grade, but we were effectively isolating segments of the slope below us. I should have dialed back my approach. The ski crampons also let me sidehill easier.
When the grade steepened, T2 came up next to me so we were standing on a slab on a steep slope next to each other. I don’t fault T2 for this at all, I would have done the same thing to discuss our route options. Our combined weight probably helped to collapse the slab though.

4. Lastly, thanks to a picture N1 took from across the bowl, we were able to see that what looked like an isolated ridge from below, was actually more of a planar wing. If we truly stayed at the narrow apex of the wing, we likely would not have triggered the slide, but the farther one steps out off the apex, the deeper into the slide zone they enter. When I saw this pic a few days later, I said “duh, of course it went, how could we be so stupid?”
That being said, views of slopes from different angles can make them look wholly different. That is to say, from below, our route appeared far more reasonable than it may have from N1’s vantage.

When viewed from the bottom of the intermediate basin, our route selection look fairly straight forward. The crown is hard to see because of lighting. We are circled. (Photo: N1)

View from N1's vantage and the story seems more simple. (Photo: N1)
Personal takeaways:

1: Group travel. Skiing is social. There are times and places for piling up and chatting, but more often than not, the thought process should be: “Are we spaced out enough?”
For the rest of the spring, I was notably more snappy if anyone got too close to my tails.
2: Spatial awareness. I got a lot of days in last season, and I feel comfortable with my terrain management skills. Sometimes, I confuse this confidence and comfort into my decision-making process. I’d do well to be more weary when we push into someplace new, and ask twice about route selection. For example: “This is the safest route up by definition. What could still go wrong? What are our alternatives and are they safer or more dangerous?”
3: Think about the slide. Billy Finley nailed this one on the head last spring in an essay on his site. Sometimes, you can do just about everything right, and it still goes wrong. So long as you are pushing it, eventually, something is going to happen. I think I have a healthy amount of respect for the mountains, and fear is often my companion. That being said, as with so many other backcountry travelers, too often my only train of thought is avalanche avoidance, and not avalanche action and response as well. We don’t often think about how our current dress, gear load, topographical position, and location relative to our partners will impact us in a slide or after. Not all those factors are controllable at any given time either. Nonetheless, certain lessons were well worth paying attention too. My crampons would have made it impossible for me to ever ski downhill. In a bigger slide, or in more exposed terrain, I should probably think about exiting my bindings as a first course of action in a slide. Also, if I was using crampons, why didn’t I have a whippet?
My snowpants were zipped open at the legs to vent. When I fell into the mix, they began to fill with snow. Had I been buried, this would have expedited hypothermia. Old timers sometimes say, “wear what you want to be buried in.”
I can’t say I’ve figured out how to keep heat in check and still keep layers on, but its something to work on more.

4: We were really lucky: No, not just because we lived, and no one was hurt, but because the experience was incredibly enlightening. I would never tell someone to jump into a slide, but I also could not have asked for a more hands on experience. I have made assumptions about what happens in a slide from what I’ve watched in the mountains, and listened and read of other’s experiences, but nothing will replace being there. The allusion of having control, the bouncing along on the bed surface, the thought process, they were all lessons learned and stored; though all slides are different, and none are worth tangling with in the end.

1 comment:

JennyN said...

Jesus, Dante! Glad you're OK.
"The only rule I got is if you slide, get up." — Bill Lee