Avi experiences

never been caught in a slide, and intentionally set off plenty of small slides (usually ski cutting) to make a slope safe to play on, but twice I've been kinda caught by surprise.

Baker- Table Mtn. vicinity  2005-    Dug pits on adjacent slope prior to skiing down, yellow light conditions, top 12" was failing, but we figured the slope was small, it wasn't that steep, and the runout was safe.   First guy down was on AT gear...no problems.  I was the second guy on the slope.  First AT skier was very light on his turns, never edging very hard.  I was on tele gear, and on my second turn I edged hard and did a jump tele turn...as I landed, a crack shot out from the tip of my downhill ski and zippered across the slope.  Nothing fractured above me, but a fairly wide swath of the top 12" slide down the slope.   We knew it had the potential to slide, but felt that given that it was a small slope and the slab wasn't huge, if it went, it would fracture only below us and not above...and fortunately that was the case. 

Baker, June 2004 Park glacier-
A week after Lowell had skied the watson's traverse and wrote it up on TAY, I was eager to give it a try.  It was a case of where 'summit (or maybe it was traverse) fever' overpowered 'common sense'.  It had snowed a lot the week before and Lowell had skied some pretty incredible late season powder on the Park glacier, but now it was sunny and warm and the week of dry weather hadn't been enough time for the new snow to fully consolidate.  There was an obvious suncrust on the climb up, but I didn't really think about what it would be like when that crust melted off.
Starting down the glacier we stayed up on the suportive suncrust, but about midway down the Park, the suncrust had melted away and we were wallowing in calf-deep elephant snot (calf-deep with skis on).  Unforunately at that point, it was really too late to reverse our path and go back up and over the summit, so we picked our way down.
Even though the glacier is really mellow, maybe 15-20 degrees?, I was causing the top two feet of snow to release and slide.  I snowplowed down the glacier with these spooky waves forming at my ski tails that caused a wide swath of snow to slide like tons of liquid concrete down the glacier, and spill into the crevasses below.   This only lasted for about 700-1000vf, but it was awful stuff...you wouldn't have necessarily been able to get buried in it, but it would've taken you for a ride, potentially into a crevasse, if ya got caught in it.   I should've recognized the snow conditions on the way up and realized the park glacier had been in the sun for hours longer than the coleman-deming and would be a melted mess.

My two burial experiences happened long ago, but are still vivid in my memory. Both were in "front country" terrain (within ski area boundaries, but not on marked or maintained runs) and required a bit of hiking to get to.

Crystal Mt., 1970. I considered myself a strong skier because of my alpine racing background, but was clueless about avalanches. I was the second skier to drop into a steep and narrow bowl; my friend had felt the snowpack begin to break loose and safely traversed out to the left. A 22-24" slab broke loose and hit me from behind, taking me for a rumble-tumble ride (somersaulting repeatedly at 60 mph) for about 100 yards. I was fortunate enough to travel over a few small trees that flipped me up to the surface near the end of the ride and ended up right-side-up. I was near enough to the surface to be able to move my head and see some light as well as take shallow breaths - everything else was totally immobilized. My friends dug me out in about 15 minutes using hands and skis; I'm very lucky to have survived this one.

Snowbird, UT, 1973. Not quite so clueless, but decided to drop in anyway with no stability testing or ski cutting (my friends had skied another easier to access line. A 3 foot slab broke loose on my third turn, but I was able to stay upright and work my way to one side of the avy path, where I grabbed a tree and held on. Mostly buried, but able to dig myself out in about 10 minutes.

The next year I had my first exposure to beacon use and avalanche prediction/avoidance with heli-guides at Mike Weigele's in BC. Since then I've taken some classes and (knock wood) not been buried, though each year I seem to set off 2 or 3 significant slides from the top of slopes, usually by ski cutting.

I've been in lots of little avalanches. I have this guilty pleasure of setting off little avalanches on purpose all the time.

My one big scare came on Shuksan arm during the Winter of 2004-2005. There was a bomber rain crust, with 18 inches of soft slab on top. We were very suspicious that it would slide, and confident that the rain welded snow below wasn't going anywhere. I was the second down the slope... it fractured, I yelled avalanche, and i was able to get an edge in the bed surface and, being near the top of the fracture, was able to stop myself and watch it go.

Wouldn't have killed me, but could have broken a leg.

Other than that, I'm like Lowell, I ski inbounds when its dicey (and just set off avalanches there).

-Matt

Other than the numerous predictable surface sluffs, mostly in spring, I have had only a couple of experiences that were significant. No burial incidents. One was on Mazama Ridge at Rainier during an overnight trip in winter. It was windy and snowing hard all night, at least 12 inches new during the night, and not very much below freezing, so the snow was very cohesive. In the morning we went over to west facing slopes, windward, above the Paradise Valley road. My partner went first and disappeared just out of sight below the top edge and band of trees. This was bad strategy on our part, but we were going down from the top of a windward slope so it didn't seem like it should be a big problem. When I started down and got through the band of trees at the top, I found myself standing on a piece of slab that had slid a few inches, and directly below me was a ~15" fracture crown and a lot of slab chunks in the trees below. At first I didn't see my partner and was very concerned, but it turned out he had skied out to the side. Standing on the area of ready-to-slide slab I very carefully side-stepped up off of it into trees and then made my way down through trees. Even though we knew that conditions were problematic, I think we were misled by thinking that the slope should be OK because it was windward, but as it turned out I think that area was actually in the lee of trees, which essentially made it a lee slope and allowed it to drift in.

The other experience was on a 30-35 degree, 1000 foot SW to W-facing slope near Snoqualmie Pass in spring (May probably). Booting up I was becoming more and more concerned about the weak surface layer of large-grained snow, which got to be 12 inches deep as we neared the top of the ridge. We stuck to the very edge of a narrow band of trees, on its south side, that ran all the way up the slope, but even venturing 6-8 feet away from the trees it was clear that the snow was primed to go. After we had gotten our skis on, I did a ski cut and the snow started sliding, ski width at first but fanning out wider and wider, taking all of the rotten snow along the way. The most impressive part was when the slide started pouring through the trees at the bottom of the slope - glad no one was in the slide to be strained out by the trees. The amount of avalanche debris in the forest at the bottom of the slope was amazing. We probably could have skied the slope safely at that point, but decided to take a look at the snow on the other side (north) of the band of trees we had ascended along. This snow was completely different - consolidated, perfect corn! We skied that slope twice.

Like Lowell and others, I generally stick to in-bounds lift skiing when the avy hazard is high. I generally ski about 40+ lift days a year. I don't keep real close track of how many backcountry days I ski per year, but it's probably around 20-to-30.

I've had a couple of close-calls with wet slides over the years, but the 2 events that stand out the most were my 2 slab experiences.

My first slab slide experience was back in the record snowfall year at Baker in January 1999. I was on snowshoes near Bagley Lakes (north of Table Mountain), working on snow depth measurements for a college project. I had basic avy awareness training at the time, but vastly underestimated the potential of a small slope I was traversing (about 100-feet above the upper Bagley Lake outlet stream). My project partner was on AT gear and cut the convex roll above me (poor decisions on both our parts) and triggered a 10-inch soft slab which propagated to about 40 feet wide; I wasn't caught, but the side of the slab broke away right at my feet. The slide was probably not big enough for a complete burial, but nonetheless was a very spooky experience.

The scariest avy experience I've had by far was with a professional guide service while heli-skiing in New Zealand in August 2006 (middle of the New Zealand winter). Avy conditions were obviously bad that day (recent slides on every aspect, persistent weak layers beneath about a meter of wind-affected snow from a big storm 2 days prior). In retrospect, I probably should've just gone lift skiing that day instead.

The lead guide had been sticking to generally mellow terrain and wind-ward aspects through the day. The group I was in voted to ski an additional run at the end of the day for an additional charge (which I had voted against, but was essentially forced to go on).

The shorter of the long story is that poor terrain selection and bad group management resulted in a nearly tragic last run. The lead guide selected a steeper (~35-degree steepness) slope in a large open bowl which the lead group (which I was in) skied first without incident (though I was looking over my shoulder every other turn to see if the slope was coming down with me). This slope made me particularly nervous as there was a bad terrain trap (gully) at the bottom of the runout.

As the group I was in traversed to the lower edge of the bowl (below a ridgeline with a topographic knoll above us), a skier in the second guided group behind us cut a wind-loaded slope and triggered a slab above us. The slab propagated rapidly across a buried weak layer about 90 cm deep (facets) and ended up triggering the whole upper basin along with an adjacent aspect around a ridge. I recall thinking that we were done (no escape route as there was that confining gully/terrain trap below us), or at the very least hoping it wouldn't be a deep burial. The powder cloud raced down the slope and engulfed the group. I braced awaiting for the impact of the debris in the white wind, though when the powder cloud cleared, I found myself still upright and standing in the same spot. By pure chance/luck the topographic knoll above me had diverted the slide debris around either side of the guide and myself. Two skiers a short distance behind me were caught and carried about 50-to-100 feet downslope and partially buried (armpit deep). Fortunately they were uninjured and able to dig themselves out relatively quickly. The guide estimated the size of the slide to be a class 2.5.

(Knock on wood) I don't ever want to have an experience like that ever again (or any more slab encounters for that matter), and I'm reluctant about using guide services in the future (just my interpretation, but this particular guide service seemed driven to take higher risks for their more eager clientele and make more money off extra runs; needless to say I was quite annoyed that the guide service still charged me (albeit a discounted rate) for the extra ski run that nearly ended tragically).

I have never been involved in a serious slab incident but have experienced both wet and dry loose snow sluffs.

Number of ski days varies widely, maybe 40 last season with about half of them BC.

In low density unconsolidated snow in the Alpental BC, I stopped after boarding several hundred feet of 35-40 degree slope. Without any audible warning I was hit from behind by a sluff about 2 feet total depth. I managed not to go down but riding with it for a short distance was a real eye opener.

Near stevens pass, after skiing a long open 30-35 degree slope, I shifted skiers right about 50 feet because the previous fall line ended in trees. Looking back left, I was being paced by a 25 foot high cloud. The temp was in the low 20's with about 2 feet of low density unconsolidated snow. I suspect the core of the cloud was also low density but I was grateful I didn't have to find out the hard way.

East of Stevens pass, I ski cut the top of a 100 foot slope that had been sun exposed above freezing with about 2 feet of snow (before consolidating) from two days prior. The slope broke at my ski cut about a foot deep. It wouldn't have been enough for a complete burial but it ran maybe 60 feet into trees. Terrrain trap combined with the high density snow could have been unpleasant.

I have often triggered the slithering loose wet snow slides in spring. One in particular near Humpback that ran about 100 feet wide and ran 4 to 5 hundred feet with about 150 vertical feet moving at one time. It was only moving 5-10 mph and you could easily have skied all over it.

-I always wonder with with these slow moving spring slides, they don't seem dangerous by themselves but how likely are they to propagate deeper slides? Has anyone seen one trigger a bigger slide?

Having seen the remnants from a slab with a 5 foot crown, I hope I never see a big one in action.