picking your brains

[medicsandy]

Ok, was reading about the skier that is missing on Crystal. Used to ski there a lot when I was in high school. Anyway....they talked about him probably falling through a tree well. I'd never heard of them before. So.....here's my question: if these dangerous wells form around trees, are there dangerous areas like that around rocks up on the mountains?? We tend to stop to rest and re-fuel on a rock. Anything we should be aware of around them?? Found it interesting.

[mattp]

Sandy,

 

Hike, snowshoe or ski through the woods in a heavy snowpack area and you will find deep holes around the conifer trees. I think these occur because snow falling on the trees remains on the branches and does not reach the ground. With our sub-alpine trees having downward sloping branches to shed rather than carry snow, some snow may be "shed" outside the profile of the tree but much is also melted as it sits on the branches and never reaches the ground. Either way, spaces between the trees are more deeply buried than are the areas immediately around tree trunks. These tree wells can be deep, and often have very steep sides.

 

You may find a wind scoop around rocks that may be exposed to wind. This is the result of the fact that when the wind hits that rock, some of its effect can be diverted downward.

 

I'm not sure about how someone would have been trapped by "falling through" as mentioned in your post. Perhaps "falling in" is a better descriptor.

 

Taking shelter in a tree-well is not a dangerous proposition. Skiers and boarders sometimes fall in and are caught there as a result of how they fell in (their skis may be hung up in tree branches or they may have been injured when they hit the tree trunk or something). Taking shelter behind a rock is not particularly dangerous either, though I have nearly been injured falling into a wind-scoop next to a rock when skiing in whiteout conditions.

[genepires]

something similar to moats tends to form around boulders. I have fallen into some of these when going across a buried boulder field in the springtime. But these should not be big enough to fall completely in. More on an annoyance really.

 

Some poor guy fell into a tree well at stevens a couple years back and died inside. A strange thing indeed.

Not that familiar with the phenomena , but I think that a dip forms in the snow around the trunk. When someone falls over and goes into the well, maybe snow from the tree and sides of the well fall into the well, burying the skier. This action would not happen around a boulder.

[mattp]

The "moat" around a boulder that Gene refers to may be more akin to thin ice that often is found around the perimeter of frozen lakes.

 

Very often, you will find that you fall into a lake when entering or leaving the ice but the actual main body of ice is plenty strong. I think this is probably because the ground around the perimeter of the lake is closer to the surface, and to where the ice would or did not form. Ground is warmer than freezing and the ice is therefore not as thick when it is formed near solid ground.

 

The same kind of thing happens around rocks. A buried rock, which either has some intrinsic warmth itself or maybe due to a transfer of heat from the ground below, seems to have a tendency to melt the snow around it and thereby create a void that lies beneath the surface that is not detectable from above-surface observation.

 

In the case of both the buried rock or the shoreline around the lake it may be that the phenomenon has to do with a penetration of sun rays through the snow or ice surface, heating the buried rock or the shoreline.

 

Anybody have information or theories?

[pcg]

When someone falls over and goes into the well, maybe snow from the tree and sides of the well fall into the well, burying the skier. This action would not happen around a boulder.

Exactly, it happens with trees, but not with boulders.

 

It's a region of loose, unconsolidated snow under the tree branches. Falling in feet first is an enormous inconvenience at best. Falling in head first can quickly be fatal as the snow caves in around and suffocates you.

 

This is a big reason why you should always ski with a buddy if you ski trees. Even that is no guarantee of safety. Three years ago a snowboarder died at Mt. Hood Meadows when he fell in a tree well right under a lift line. He was with friends, but it took them and others 15 minutes to extract him and by then it was too late.

 

Deaths from tree wells are common enough that they have their own acronym - NARSID, for non-avalanche related snow immersion death.

 

Back to boulders, another hazard to skiers is skiing into a "blow hole" when visibility is poor. On big flat areas like Zig Zag Glacier on Mt. Hood these boulders get buried during the winter, but the hole created by the wind blowing around them persists and can be an ugly trap that is hard to see in flat light or whiteout.

 

Edited March 15, 2011 by pcg

[Dave A.]

I have fallen into voids around rocks like you describe and was fortunate not to get hurt. The voids can be rather large, much like a crevasse under a snow bridge. There is a field of large boulders on Mt. Cashmere where you can look down sometimes 20 or more feet. These can be covered by thin layers of snow in the spring or early summer and would be deadly if you punched through. The tree wells can also be covered over by blown snow and not be visible at all. I fell into a small one, and I'm not sure I could have got out but was fortunate that my arm with my ice axe was sticking out and I hooked a nearby tree branch. A very good reason not to hike alone.

 

 

 

[pcg]

There is a field of large boulders on Mt. Cashmere where you can look down sometimes 20 or more feet. These can be covered by thin layers of snow in the spring or early summer and would be deadly if you punched through.

I was wrong then. I've never encountered this. Thanks for the heads up.

Edited March 15, 2011 by pcg

[snoboy]

Mt Baker, Crystal Mtn, and a couple others collaborated to produce some excellent info on tree well safety:

 

http://treewelldeepsnowsafety.com/

[gyro]

The void areas around trees and rocks can be caused by the rock or tree being heated by the sun. The object absorbs the energy and radiates it through its mass, melting nearby snow. I've seen some large hollows around boulders as well as trees. Like Dave.A said, they can get big; I punched into one and was over my head. Fortunately it was consolidated snow/ice and didn't cave in on me and I was able to get out eventually, but it was hard.

 

Ever since then I avoid trees and boulders early season like the plague.

[medicsandy]

Interesting stuff. Thanks for the answers. Haven't been on here for a while....i've been out hiking my ass off in prep for my first Rainier climb. I remember hearing about a rescue up around Muir where a guy fell through the snow into freezing water and had to be rescued. Would this have been around the rocks?? I guess what I'm really wondering is....if i sneak off to take a pee....should i avoid getting too close to the rocks?? Lord knows I don't want to get hauled out with my pants around my ankles and my charmin in hand!

[grandpa]

Interesting stuff...Lord knows I don't want to get hauled out with my pants around my ankles and my charmin in hand!

 

Now, that's the funniest thing I've read all week! ...and I agree, that wouldn't be the greatest.

 

I'll be with you in spirit, but I had to turn back the opening in July. I have new pins, screws and some wire in my foot, so gotta get that all back to 100% first, maybe September. Have fun!

 

 

[medicsandy]

awww....was keeping my fingers crossed that you could climb with us! there's always another day and another mountain. we'll climb together....i'm sure of it!

p.s. i'll bring the charmin!!!

[grandpa]

awww....was keeping my fingers crossed that you could climb with us! there's always another day and another mountain. we'll climb together....i'm sure of it!

p.s. i'll bring the charmin!!!

 

Yeah, so was I. I'm tentatively considering a summit this September, doc said foot should be good by then. Then again next summer. Fergit the charmin, send pics!

[medicsandy]

KING 5 just put this out yesterday on the tree wells.

http://www.king5.com/video/featured-videos/Dangers-of-tree-wells--118887944.html

[Dave A.]

Good video medicsandy. Thanks for sharing. Dave A.

[BirdDog]

Lord knows I don't want to get hauled out with my pants around my ankles and my charmin in hand!

 

Years back skiing at Crystal I saw a gal crouched over, ski pants down around her boots, bare butt, skiing backwards out of the trees across the groomer; screaming! I assumed she had skied into the trees for some privacy. Always make sure your skiis are perpendicular to the fall line when stopped.

 

OK, back to tree wells.

[gyro]

Years back skiing at Crystal I saw a gal crouched over, ski pants down around her boots, bare butt, skiing backwards out of the trees across the groomer; screaming! I assumed she had skied into the trees for some privacy. Always make sure your skiis are perpendicular to the fall line when stopped.

 

That's awesome. Not nearly as embarrassing but this last winter I was skiing at schweitzer and was practicing turning 180 degrees, skiing backwards for a bit, and then flipping back around. One turn I managed to hit the latch on my AT bindings holding my heel in place and suddenly I was going downhill free-heeling one foot trying to clip it back on while some random person was videotaping me. I must have looked like some unholy flailing mess shooting down the slope backwards flailing at my boot.

 

What was that about tree wells?

[medicsandy]

too funny gyro! would love to see that video. were you screaming like a girl??

wonder if you're on you tube! ha!

ok, now back to tree wells.....or awesomely stupid things we've all done.

 

[medicsandy]

Update on this post from back in March. I just heard on a Crystal Mountain blog that they just found the missing skier a few days ago. He WAS in a tree well. http://sports.espn.go.com/action/freeskiing/news/story?id=6669936