Mt Whitney Zone Forums General Discussion Missing Snowboarder Found Dead in Tree Well (North Sierra)

Missing Snowboarder Found Dead

By Kim Minugh and Bill Lindelof
December 30, 2010
kminugh@sacbee.com

The search for a missing snowboarder near the Alpine Meadows Ski Resort came to a tragic conclusion this morning when rescuers found her body in a tree well, according to authorities.

Rescue helicopter crews spotted the body of 25-year-old Shawnte Marie Willis of Tahoma this morning on a part of the mountain that previously had been off-limits to rescue crews because of inclement weather, Placer County sheriff's Capt. Jeff Ausnow said in a press conference.

Authorities believe Willis might have hit a tree while snowboarding, Ausnow said. Her body was found in a tree well.

"The news is tragic," Ausnow said.

Willis went missing Tuesday afternoon. Search and rescue efforts were hampered by high winds and low visibility that prevented the use of search vehicles including helicopters and snowmobiles. Blowing snow also had covered any tracks.

Ausnow described the area, which is U.S. Forest Service land, as "treacherous," and said 80- to 100-mile an hour winds had been blowing there.

"The weather would not allow us to get there," he said.

Ground search crews were called off Wednesday because of the threat of avalanches. However, Ausnow said today there were no obvious signs of an avalanche in the area where Willis' body was found.

Although it happened on the other side of the world, and was hot, not cold, there is a common thread. It's called "climbing the fence". The exact same reason why we get an involuntary skydiver from the top of Vernal falls every year or two.

Note that the temperature given is in degrees Celsius, not Farenheit.

for those not familiar with tree wells
Tree wells

I wonder how many times it is due to the skier or snowboarder passing over an the unseen roof (like a snow bridge) that collapses into a unseen well that has a larger circumference around the tree than one imagines? (Kinda like on glaciers, it's the crevasses you don't see that are the problem.)

You would think the vast majority are like that, because otherwise it would be people just careening out of control into obvious holes.

Why would you think there aren't enough "careening out of control" to generate the toll we've seen in tree wells? The only deaths I've seen reported due to unseen (non-tree, non-stream) wells were in the hollow over the steam vent on Mammoth that formed during a very high accumulation rate storm. Those weren't even Non-Avalanche Related Snow Immersion Deaths (NARSID), but poison gas deaths.

Dale B. Dalrymple
http://dbdimages.com

hmm, let me please restate my theoretical question

excluding all those speeding, drunk, blind, unskilled, lost, fog-bound, or testosterone-fueled skiers or boarders who fall into a hole, could there be some innocent skiers who pass too close to the edge of a visible tree hole or a roof/snow bridge over a hidden tree hole and therefore cave it in? Their eventual upside down or tangled condition may not always be the clue to what happened in the first microsecond. And, if there was a cave-in under them, it would not be so obvious when they are found because it is under them rather than on top of them. Is this possible? Are there enough tree hole survivors or SAR reports to answer this? Just shooting the breeze here.

The Mammoth incident sort of proves the point doesn't it? These were knowledgeable ski patrol people who got close to the edge of a known (steam) hole and the edge caved in. Is that right?

Disclaimer: I am an intermediate skier with Western experience only on groomed trails at Vail and Mammoth.

Harvey

Harvey, that's an interesting question. My experience of tree wells is that they are a steep bowl with the bottom at the tree, or with a space that has been filled with spindrift...so that it LOOKS like it is a snow surface, but is a spindrift trap. The surface is a steep slope down, filled with drift, if there is anything there at all. The drift, sort of like skiing in fresh powder, takes on the properties of a fluid rather than a solid. Push on it, and there is no purchase, and this is why it is so hard to get out.

The Mammoth situation was quite different, where the steam created a underlying melt...somewhat what can happen with a stream and a snow bridge. It created a void under the surface that progressively lost strength, then gave way. They fell into a clear space.

As I understand it, quite different mechanisms.

Could you give me a little background on what happened at Mammoth with the steam hole (I am unfamiliar with the incident)

Harvey, I spent many seasons in the local backcountry to where we stayed in the mountains, and I can remember being surprised at how far away from the "drip-line" the instability of the tree well extended (a lot of them actually had a high branch start, but still had a well.)

I think the problem with this incident was that the steam hole does not normally cover over, but continues to maintain an opening as snow falls. This time a rare high accumulation rate managed to cover the hole. When the patrol went out to set up the usual flagging around the vent there was no hole marking the vent. While they were putting up the markers, the cavity collapsed.

Overhanging powder is a tough climb out and a tough extraction to rig even if you can stand upright.

Dale B. Dalrymple

yep, plus it was not just steam, but poisonous volcanic gasses, which overcame the patrollers within a very short time (<2 min as I recall). I believe one guy jumped down to help and was lost.

Here's an article:

http://www.mammothlocal.com/news/3_ski_patrollers_die.php

Thank you for the background, Ken. A very sad accident.

Ken and Bee thanks.

Both seem to confirm my theory that a soft, unconsolidated spindrift-filled cavity could look safe or even be totally unsuspected. Then, when the innocent skier or boarder comes by too close to the tree, the black hole sucks him or her in. The unwitnessed event cannot be analyzed by their partner or SAR, both who assume the victim did something stupid.

Maybe there should be catchy (but not 100% guaranteed) rule for how many feet away one should pass from a tree in heavy snow ares, something like "Four is poor, eight is great." I imagine it should be more.

Edit: I now see there is more info on another thread here
http://www.whitneyzone.com/wz/ubbthreads.php/topics/9726/Skier_Missing_in_China_Peak#Post9726

PS: I just emailed these guys about my question:
http://treewelldeepsnowsafety.com/

Ignorance is not innocence. As the people at http://treewelldeepsnowsafety.com/ point out:
"...a tree well is a hole in the deep snow, which is clearly marked by a tree. You can easily identify and avoid these areas."
The "unwitnessed event" can be easily analyzed by the presence of the tree. As Ken's postings on shelter building point out, a knowledgeable traveler can use a tree well as a temporary shelter. The same knowledge can be used to avoid acquiring permanent and final shelter.

Dale B. Dalrymple

I don't think there is much tree well awareness in the central Sierras as the snow doesn't generally get so deep that they are a problem. The dumps we've had so far this year have set up tree well conditions and hopefully some info will be posted at the ski areas.

I beelieve that the learning curve for life outside the groomed slopes is going to have to be very steep this year. Casual trail bangers such as myself are not used to tree wells and avalanche warnings. Life in the lower (our stomping grounds are a good 3-4K lower than the eastern playgrounds) western Sierra is usually uneventful as far as hazzards go.

The issue I raise is not whether an obvious tree marks the obvious spot, but how far away from that obvious signpost must one be to avoid "cave in" of a dangerous loose-spindrift roof or bank around the tree. I realize there is no perfect number.

Bee knows I am just trying to understand Mother Nature. I don't have the answers, but sometimes a question from a newbie (re: tree holes) can occasionally be useful, at least to me, and maybe others. Thanks.

Harvey

I definitely know where you are coming from, Harvey, because I have been pummeling Mike (who has more familiarity with the phenom than any of my other friends) with questions, trying to build a "perameter" in my head. Unfortunately, every time I seem to set up an "if-then", Mike throws in yet another variation to the rule.

Example: Small-size trees that become fully buried during a huge one-time snowfall (like this last week) Many of the cross-country areas that Mike and Billy(bill-e-g) frequent now have a nice, clear meadowy look about them, but these buried 5-7' trees can become unpleasant tree-well landmines.

There's a variation of these tree wells which you can encounter when peakbagging in northern New England which are called "spruce traps". Fortunately, they're usually not fatal, but are still very tiring when you have to dig yourself out of them.

In northern New England, there are distinct zones, based on altitude, where there's a progression of hardwoods down low, then white birch, and then spruce before treeline. It's in the spruces that you have to use care. You can avoid the obvious - getting too close to an obvious tree. The "trap" occurs when you snowshoe over a small tree - maybe 3'-4' tall - hidden under the snow. Sometimes you plunge up to your armpits, and the snowshoes get tangled the branches. It's no fun, and sometimes requires the help of your companions to get you out.

More on bole holes from today's Fresno Bee: Deep pits around trees pose deadly risk on ski slopes.

"Even tree wells that form around relatively small trees can be deadly. The red fir that Shelby fell into is about 20 feet tall and its trunk 8 inches in circumference with plenty of low-hanging branches heavily loaded with snow, China Peak director of mountain operations Rich Bailey said. Much of that snow likely fell on top of Shelby when he tumbled through the branches. "It surprised me when I saw it," Bailey said. "But even a tree that small can swallow you up, cover you with snow and no one would know a thing unless they saw you fall in.""

"Two experiments conducted in the U.S. and Canada in which volunteers were placed upside down in a tree well found that 90% could not extricate themselves, according to the website www.treewelldeepsnowsafety.com."

Written by our favorite reporter, Marek Warzawski.

Of 12 ski deaths in Western North America in the last month, 4 skiers were eaten by tree wells.

Edit 4-20-11: Excellent tree well rescue video here: Tree well rescue

...and a related thread: Skier Missing (Tree Well Information)