February 16
th was the kind of bad day that could
have been a lot worse.
The short of the day, was that Aaron and I were skiing the
backside of Microdot in Hatcher. Climbing back up, we overtook another group of
two on what appeared to be a low consequence slope, and triggered a short,
wide, 3-foot deep slab above complicated terrain that took three of us for a
ride and left one us buried neck deep.
For a few seconds, I was certain I was going into a hole and
would be buried and maybe crushed. Luck is all that kept me on the surface in
the end. Like all days, there were a lot of decisions made, most were small,
and seemingly inconsequential. This is my attempt to look back at them, with
the advantage of hindsight, and consider what went right, and what went wrong.
Pre-Slide
After weeks without snow, Hatcher Pass had been walloped
early in the week, first by a windy and warm storm that dropped around 2 feet
of snow. I initially expected the snow to be very reactive due to the old and
wind hammered base.
Data on how the new snow what reacting on the old base was
sparse. The road to the Pass was left unplowed. Skiers struggled to get up to
Hatcher Monday or Tuesday. Mid-week, a second, colder system passed through
dropping another foot of lighter snow with minimal wind, burying clues from slides
that occurred during or after the first storm.
The road remained unplowed Wednesday and Thursday, and what
little info was coming out of the Pass offered mixed signals. Considering the
wind-hammered base the initial storm had fallen on, natural avalanches were sparse,
when it seemed they should have been rampant. There was fairly ample evidence however,
that the new snow was readily reacting to skiers.
The slides being reported were running out in typical storm
slab configurations: generally narrow, slowly, and softer in composition. These
are the types of slides one might expect as the storm abates and the snow
begins to settle down.
On Friday, with the road plowed, Aaron and I decided to go
check things out
Decisions
Decision 1:
Self-assigned danger rating of considerable. Synopsis: Correct
Hatcher has a once a week av forecast issued on Saturdays,
which was not yet out. Observation info was limited, and mixed. That being
said, the base/bed surface the snow had fallen on warranted suspicion. Based on
what I knew, I assigned a danger rating of considerable. The rating plays a
role in my personal decision making. A professional, or personal assignment of
“considerable” equals an automatic one “flag” for me. Three flags, and the day
is over.
Decision 2: Flat light
delay. Synopsis: correct.
Friday dawned with high clouds, but a forecast to clear. Given
the self-assigned considerable rating, we delayed start until noon when it was
apparent that skies were actually clearing. Hatcher is a difficult place to ski
when you can’t see. When conditions are good, you can continue to ski therein
low light, but the point of this ski was to get info. Not being able to see or
having obscured vision, was both a risk, and negated much of the purpose of
going at all.
Decision 3:
Observing a fresh skier-triggered slide and not marking it as a flag. Synopsis:
incorrect.
As we arrived, we passed Marmot’s west face, and observed a
very fresh (less than 5 minutes old) skier-triggered storm slide. It appeared
the skier had skied past a trigger point and was some ways down the slope
before they realized the slope was sliding, and safely exited the relatively
narrow slide path. The skier’s two partners skied next to the slide with no
additional reaction. I asked the ranger if he had witnessed the slide but he
said he had missed it. I suspected it was similar to the skier-triggered slides
that had been reported earlier during the week: slow-starting, deep, able to
run full path, but non-cohesive. This was concerning, but I did not consider it
a flag at the time. The slide was clearly slow, and the snow seemed somewhat
stubborn, and the slide had triggered where the skier passed by a classic
trigger point: a rock and convex protrusion.
In hindsight, these were some of, if not the first skiers on
this slope, and they had nearly instantly triggered a slide. Regardless of
whether the slide indicated a “healing” interface this should have been flag
2 for the day.
Decision 4: Pit
test – no clear decision rendered.
On the way up Microdot, we passed a pit dug by the avalanche
center. I reused the back of the pit to isolate a new column. I would not call
this a formal test, however, it was far more formal than any previous pole pits
conducted to this point. We observed a moderate force trigger, easy leverage,
and a clean shear. The pit, to me, indicated typical spatial variability, we exposed
a potential, though not widely existent, smooth bed surface. We knew this
reaction was spatially variable based on pole pits. This confirmed a suspicion
that the slides were triggering in specific locations, and were generally
sliding more due to the mass of available loose snow/inertia, but were failing
to propagate on a wide scale due to a lack of a cohesive slab structure or the
existence of a wide spread consistent bed surface and weak layer combo.
Basically, hit the right spot, you would get something to slide, and in steep
terrain it would carry enough snow to slide down the fall line, but it would do
so fairly slowly. In general, it’s not likely I’d ever commit a flag to a
single pit result in any situation, unless the pit revealed an unexpected
condition, in which case, I’d be looking to dig more pits. Pits are good for
getting a good look at layers, but are indicative of a small spatial area, especially
in Hatcher. In hindsight, this was evidence that should have been accounted for,
but not compelling.
Decision 5: Subtle
collapsing on established skin track – no clear decision rendered.
We observed subtle collapsing on an established skin track
on Micro’s rounded west side. Aaron seemed to notice this more than I did, but
Aaron is a good bit taller than me, and heavier as a result. When he commented
on this, I was able to get some very deep, muffled collapsing by jumping up and
down. The aspect where this occurred is underlain by large (and now buried)
boulders that are typically exposed; and is a wind-hammered ridge. Collapsing
was not a surprise given the sub-surface, but what was surprising, was that the
skin track was a day or more old and had been traversed by at least 8-12
skiers. Again, Similar to the pit results, this reaction, on this slope, did
not (and likely still would not) warrant a “flag,” but it should have increased
the level of suspicion, and been a clear indication thigs were not “alright.”
Decision 6: False
positive observation of skiers in Rae Wallace. Synopsis: incorrect.
This was one biggest mistakes of the day in my view. While
climbing, we observed two skiers drop into a steep and finned chute on the
western side of Rae Wallace. The skiers were cutting hard, and passed over
numerous potential trigger points, but failed to initiate anything more than
sloughing. I gave this observation immense weight, more than any other
observation to this point. Why? Because it showed what I wanted to see. I
wanted conditions to be stable, and this appeared to show it. Instead of
considering this a neutral observation (maybe they got lucky, may steep
north-facing had already slid, etc.) I overshadowed the previous observations
made.
Decision 7: Skiing
the north side and deviating from plan. Synopsis: wrong, no safe exit strategy
for conditions.
The plan had been to ski the sunny south side, however, it
was well tracked. As we topped out, a group of two descended the unskied north
side. I heard a loud collapse as the first skier dropped in, but observed no
cracks or other reactivity. The second skier, a snowboarder, dropped in next, with
no collapse. I felt good about the slope as it is concave in the center, and
punctured with micro features that break the slope and can act as snowpack
anchors. The skiers had initiated a collapse, but it was right off the ridge, not
a surprise, and there were no visible cracks. Aaron also felt good after
watching the two skiers drop in, so we followed a few minutes later. We did not
get any reactions. Skiing this slope would not cause us any problems, but we
did not have a good exit strategy, and that’s what would bite us.
Decision 8:
Climbing north side of Microdot. Synopsis, incorrect.
The snow was incredible, we were leaning toward the idea
that conditions were stable. We had the choice to either climb back up the
north side, or exit the bowl. The latter option chews up a lot of time (less
skiing), but the former would either put us on a steep slope we’d just skied when
other skiers were likely to descend on us. We could also put in a more
circuitous climb northeast of the main north side run. The two skiers in front
of us were a few minutes ahead of us, and began to break a trail, climbing this
circuitous north east route. We did not communicate with them about route
selection prior, but later confirmed that they chose this route to avoid
skinning directly up the main run, which they also assumed would have skiers
dropping in.
At the time, this seemed like a prudent decision, I was
familiar with the terrain, I had recently used this route, and felt good. In
the face of no better evidence, this might have been an OK decision. In the
face of the actual evidence observed, and having two flags already up, we
likely should have just exited the bowl.
Decision 9:
Catching and passing on a steep slope. Synopsis: too close, avalanche/incident.
This is where it all came to head. Trail breaking was slow
and deep. Aaron and I were able to catch up with the two other skiers, who I will
refer to as skiers 1a and 1b, in a sub bowl approximately 200 vertical feet
above Murphy Lake.
Skiers 1a and 1b were approaching an approximately 100-foot northerly
facing slope above the sub bowl that lead into the next, smaller bowl. This was
the incident slope. Skiers 1a and 1b were approximately 25 yards apart; 1a was
entering the incident slope, setting a skin track across the slope using a narrow
natural bench that cross-cut the slope.
In a non-judgmental way, I did not like this route, and
would have preferred to stay in the flats of the sub-bowl and use a short
concave gully on the climber’s left of the incident slope. I’d used this small
gully feature before, but, with deep snow, and a small and unintimidating
incident slope, I opted to stay the course and follow the broken track to try
to catch skier 1a and relieve them of the arduous trail breaking.
I caught up with 1a approximately mid-slope on the incident
slope, and was about 10 feet behind 1a.
Everything I’d observed to this point, barring one false
positive, should have had told me I had 2 flags raised, and the antennae should
have been on high. Getting this close to another skier on a steep (greater than
35 degrees), albeit short slope, that I did not like to begin with, over
terrain traps, was just stupid, and about to be a big mistake.
Slide
At this time, skiers 1b and Aaron were just entering the
incident slope about 25 and 27 yards respectively behind me and 1a.
As 1a and I passed a mostly buried rock outcrop, (the area
featured numerous micro features including buried boulders and micro channels),
the snowpack settled 2-3 inches.
All 4 skiers felt the settlement.
The slope began to fracture and broke an apex crown about 30
feet above skier 1a and I, and fractured approximately 150 yards across, at a
depth of 2.5-3 feet. Slope angle across the slope varied due to the micro
terrain.
Aaron was the farthest back, and on the edge of the
fracture. By turning around he was able to escape the slab.
Skier 1b deployed their airbag and was knocked down. They
were carried an estimated 25 vertical feet or more, sliding through a channel.
Skier 1b said they felt their airbag slow them down and keep them above the
moving snow.
For myself, a memory kicked in as the snow slowly crumbled
and I felt myself sink and lurch down. I turned downhill and was able to take a
stride or two before being knocked backward by the acceleration. I was in a sitting
position, upright, facing downhill, leaning back over the tails of my skis. I could
tell immediately that I was being carried directly toward a number of potential
terrain traps at the base of the slope, likely small tarns.
As the slide initiated, I in line with a low, snow-covered
ridge of rock, this feature played a role in keeping me safe. By constantly moving
my ski tips upward, while using my poles laid flat behind me (no wrist straps
attached) I was able to provide some directional steering and float above the
moving snow and ride on the higher micro terrain. I could occasionally feel the
bed surface with my fists, likely buried snow-covered rocks.
As the rock ridge narrowed and ended, the snow pulled me to the
right, toward a channel that lead into a terrain trap that I could see was
going to fill.
At this moment, I realized I had to fight with everything I
had to stay on the little ridge, or I would end up in the hole.
I plunged my left hand into the snow and planted the handle
of my left pole as hard as I could into the bed surface. The snow pushed past
me for a second and I was able to wheel leftward, redirecting myself at the
last second, to instead stay straight and ride over a 3-4 foot snow covered
ledge. The torque from the maneuver tore the pole from my hand, which was
planted with enough force it was still pointing outward after the slide.
As I spilled over the ledge, the slide lost momentum, and I
could see I was on a small alluvial feature, and was going to be OK. I was
carried an estimated 50 vertical feet according to a GPS track.
Skier 1a also turned down hill as the slide initiated,
however, 1a was directly above several terrain traps located at the base of the
slope. Skier 1a deployed their airbag. I heard the bag deploy, but never saw if
it inflated. After the incident, 1a said they believed the bag deflated during
the slide or never immediately inflated, and when I discovered 1a, there was no
evidence the bag had been inflated at the time of burial.
Skier 1a was carried right, and traveled an estimated 75
vertical feet. I was able to see skier 1a get dragged right, but lost sight of
them due to my own struggle and to a raised terrain feature.
The slide lasted an estimated 10-15 seconds, and had
effectively slipped the entire incident slope.
It was unlike any of the skier triggered slides yet
observed, and carried a classic slab pattern, including a few step downs.
Response
Aaron was off slope as the slide stopped; Skier 1b was on
top of the snow but partially hidden from view of Aaron and I as they were in a
small channeled terrain feature; I was upright at the base of the slope below the
ledge, my left leg was buried shin deep, but the tail of that ski was at least 2
feet deep, my right ski was on the surface. Skier 1a was not visible to the
rest of the group and was buried to their neck, facing down slope, slightly
reclined, and surrounded above all but their right hand.
Of note, skiers 1a and 1b also had a dog with them. It is
not clear to any of us where the dog was at the time of the slide’s initiation,
nor where the dog was after the slide. It is possible the dog was buried or
partially buried in the slide, and extricated itself, as we all distinctly
remember it appearing after the slide during the extraction of skier 1a.
I immediately called out that I was up, and OK as the slide
stopped, I could see Aaron. Aaron confirmed he was ok. About 5 seconds later,
skier 1b called that they were OK and stood up.
The three of us were now visible to each other, but could
not see skier 1a. We began to shout and call for skier 1a. No response was
heard, and there were no visible indicators of their location.
I initiated the search, and called for all beacons to be
switched to search mode.
I had the last visual of 1a, and was closest at the time of
the slide. My beacon indicated an initial distance of about 25 meters to skier
1a; Aaron, who was farthest away, had an initial reading of 65 meters.
Based on the fact that I suspected skier 1a was fully buried
in a terrain trap, and was relatively close, I chose to dig down and release my
foot from my buried left ski and abandon it rather than excavating it first. I
believed I could reach 1a as, or more quickly on foot.
I unclicked from my right ski and used it, and my remaining
pole as aids to scramble through the debris while heading in the direction I had
seen 1a carried, checking my beacon for reference.
Aaron still had both skis and skins on and was beginning his
search, however, he was father away and had to traverse the base of the debris
initially. Aaron remarked later that he was surprised how slow and challenging
it was to travel through the still-soft debris, and that he felt like he was “going
through mud.”
I called 5 meter increments, which also seemed to come
slowly, and was lead on a trajectory over the small ridged terrain feature that
divided where I had been sent and where 1a had been sent. I also initially felt
that progress was slow, however, not having skis on made it easier to scramble
a direct route across the debris and micro features since the distance was
short.
Upon climbing the small ridge feature, my readings dropped
instantly from 20 to 15 meters.
That’s when I first heard a muffled call for help.
Below me, 10 meters away or less, I spotted a glove
protruding from the snow.
I yelled “I have a hand.”
Later, 1a would say this was the first thing they heard,
despite the yelling the three of us had been shouting.
I was slightly uphill of the hand, which I still did not
know was not just a glove on the surface. I began to yell to 1a that I heard
them.
As I scrambled down, I was able to make sight contact with
1a, whose head was just barely above the surface, and yelled this to the group.
1a was buried upright, facing downhill, leaning slightly
back, buried with compact snow to their neck, loose snow to their mouth, their
right arm stuck up, their left arm buried. Though loose snow had collected
around 1a’s mouth, they had an unobstructed airway. Snow was piled about 1.5
feet above 1a, only their hand was visible on the surface, their head was
sunken into the depression.
As the slide had stopped, 1a knew it would be their last chance
to create an air pocket, and shoved their arm upward and swung it across their
face. The snow settled and instantly froze them in that position.
The time between the end of the slide and my contact with 1a
was 3-4 minutes. This was verified by a GPS track.
I assessed that 1a was breathing, conscious, able to make
eye contact, and had color in their face. At face level, I brushed loose snow
away from 1a’s mouth, and asked 1a if they were hurt, or felt any pain or
injury. 1a said they were struggling to breath; 1a’s breathing and speech was
audibly labored, this being due to the weight of snow on their chest.
I chose to forgo any further potential injury assessment,
and began to excavate snow away from 1a’s chest.
I carry my shovel with the handle in place so it can be
deployed in a single motion. If you don’t do this, you’re wasting time.
Adrenaline will be on high in these moments, stupid things like sliding a
shovel shaft into the blade will be stupidly slow. Everything you do to make
the search faster are an aid, whether it’s easy access to your beacon, or
rescue equipment.
Despite the adrenaline, I was aware that I kept a high
situational awareness, watching for near or far hang fire.
Even as the urge to want to start digging furiously set in,
I made sure to tuck my beacon back into my jacket, closed the zipper, and
situated my pack uphill and away from where I’d be excavating snow. These were
all conscious decisions that happened. I was aware they were happening, but
they all felt automatic. I can only attribute this to both practicing for this,
and for rehearsing it mentally.
Approximately 1 minute after I arrived, Aaron arrived. Aaron
deployed his shovel and began to assist removing accumulated snow, forming a
shovel train.
Here’s where I made a mistake, albeit, a small one: Aaron,
like I, was relieved to see skier 1a above the snow, conscious, etc. I never
communicated to Aaron that 1a was struggling to breath though. To this point,
communication had been good, but lacking that knowledge, Arron did not know
there was still urgency to the situation. This came up after the incident, but
it was worth noting.
Skier 1b arrived about 1 minute after Aaron. 1b was
emotionally upset from the incident, and relieved to find their partner well.
After a few minutes of excavating 1a down to their waist, I slowed
and asked 1a to re-assess for potential injuries. 1a said they felt good, other
than a sore knee. 1a was now able to breath easily and to communicate fully. I continued
to excavate behind 1a, as well as to dig to 1a’s feet so I could release 1a’s
skis, which were both still attached. I did my best to avoid knocking more snow
on 1a, and communicated clearly when I was moving blocks of snow away from and
behind their head, knowing that the sensation of reburial can cause panic in
these situations. 1a was calm and collected the entire time.
Once free of 1a’s skis, I used 1a’s backpack straps to pull
1a fully free.
Post-incident
The group spent some time after the response discussing the
incident and assessing conditions that had lead up to the slide. Both groups
agreed that while there was evidence of instability, there were also not as
many typical flags, nor ample evidence of flags. Skiers 1a and 1b had reported
they had been snow machine skiing in the area the day prior, and reported that
they had spent the day easing onto progressively steeper slopes with no results
or reactivity. Aaron and I had noted what we saw as inconsistent activity,
indicative of spatial variability. None of the skiers in the groups had
conducted their own formal stability tests. Experience levels in the group were
high. All skiers involved in the incident had 10 or more years of backcountry
skiing experience.
All skiers involved agreed that spacing and slope angle
where a problem, particularly given that there were signs of instability.
At the time of the incident, I had approached within 10 feet
of skier 1a. Who knows whether better spacing could have prevented the
incident, or whether it still may have caused a slide as 1a passed, or delayed
the slide until myself, 1b, or Aaron passed.
Skiers 1a and 1b were not upset, they, like myself, did not
suspect the slope to be a threat. To the point, not knowing whether the slide
would have triggered because of spacing, they were thankful we had decided to
follow them. No other skiers would ski the north side of Microdot that day.
Another factor that contributed to the slide, these bowls
are in a sheltered, northerly facing terrain feature. With additional
protection provided by the small micro features. They were likely points to
harbor buried surface facets over the wind hammered base that had been proving
to be a reactive layer over the buried bed surface elsewhere. Our previous
travels had been on aspects that likely would have seen the facets wiped away.
On first glance, the relatively small size of the slope, and
apparent “slope anchoring” provided by these micro terrain features, might have
given the impression that while steep, the slope was not high risk. Over a flat
run out, or with a smaller snow load, the slope would not have necessarily been
problematic, but given the snow load, the two flags that were up, the evidence
that conditions were still unsettled and variable, and existence of terrain
traps, this slope deserved better travel protocol, or avoidance entirely.
Interestingly, we had intentionally avoided the main north side slope expecting
skiers to enter it, but no one ever did.
After the slide, we all skied back down our skin track to
Murphy Lake, then across the lake, and back down to Independence Mine.
Root Causes
Personal: I want to see what I want to see. I want stable
snow so I can go ski the lines that engage me. Lacking snapping red flags, I
chose to focus on evidence that leant itself toward stability, and ignored or
dismissed the evidence to the contrary.
Protocol: had I been willing to see the evidence for what it
was, I would have been more concerned with both route selection and spacing. While
my intentions were good to catch up, I should have waited before crossing the
incident slope, and caught up with 1a on the flat above.
It sucks to know you messed up. The biggest take away for
me, was the reminder that I need to ease up. I have a habit of seeing what I
want. There’s a balance. This sport is inherently risky, it is uncontrolled,
and thus risk management is subjective and personal.
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| View from below. T is the trigger point, black line was the skin track, 1a is where skier 1a was buried |
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| View of the approach slope. |
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| Burial location. Good example of how a relatively small slide can pile a lot of snow in the right features |
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| Not great shots of two skier-triggered slides on Marmot. The slide to the right was triggered as we arrived, the slide to the left was triggered moments before we left. |
