Indy pass slides 10/26/09

[leroy jenkins]

Witnessed a few slides today, both natural and skier triggered.

We noticed this natural release on the way up.



Before any internet second guessing takes place, I'll mention that the line that slide had significantly more snow than the lines that were skied, and the slide path was also below a significant cornice. I thought I got a better pic showing the starting zone, but I guess I didn't. It appeared to have started when wind loading that had stuck to the cornice broke, triggering the rest of it. Only the new snow from last night slid, about 1', which was heavily windloaded and thick. The bowl is a westerly aspect, with that particular chute facing a bit more northerly.

On my first run I kicked off this.



I cut the cornice with my ski pole getting small sections to break. When I'd cleared a five foot section, I dropped in with a tiny bit of speed, on the lower edge of my cleared section, angling towards the shallow shoulder. I expected the cornice to break, and planned on it breaking just above me, and pointing it with speed into the safe zone. I thought the chute might slide, but was still surprised when it did. Once I was in the safe zone I sat down and dug in pretty quickly just in case, and I managed to get a look over my shoulder, the chunk of the cornice that broke off was not very large, its hard to guess, but probably around 300 lbs. Not too much heavier than a person with gear really.

The (very) small slide to the right was triggered after mine simply by someone cutting the cornice with their pole.

Here's a closer look at the slide I triggered. You can't quite see, but the safe zone I went into had a pretty flat area, with a shallow enough snowpack I could have dug into the rocks if I'd needed to, and had no cornice above me.



This slide, along with a couple other natural point release's we saw from last night, were all the new snow sliding on top of all the old stuff. Most of these slides probably would not be fatal to be caught in, but the possibility for serious trauma from rocks still exists.

[JoeStrummer]

How is the snow? Worth a drive up from Denver before the road closes?

[leroy jenkins]

Snow is damn good. Solid base with soft stuff on top. Competition for lines is getting pretty fierce though, since there still isn't all that much stuff thats skiable. There were probably over 20 people out yesterday, and everything in sight got shredded multiple times by the time we left, and there were still more people heading up. We're supposed to get a bunch more snow soon, which would open up a lot more terrain coverage wise, but may also send the avy danger through the roof, so I guess who knows.

[bobbuilds]

looks good.

[JoeStrummer]

I'll probably come up early tomorrow, weather dependent. Looks too good to miss.

[summit]

One common thread in virtually every skiing avalanche incident this season has been that the slab has not broken until the skier is well out on it and it has occured during attempts to "cut." The presence of recent natural avalanches should be a red flag waving in your face. It is good to be thinking about things like safety zones and escape routes, but don't let the competition for good lines allow you to get suckered onto these slabs. If you don't think that a 300# piece of cornice will mess you up, you might be in for a surprise.

[pechelman]

a couple of things that were on my list to evaluate with much more scrutiny in the upcoming season.

a) ski cuts as a tool for determining stability (or rather not to be used as one)
b) are chosen safe zones really safe

thanks for the reminder

[leroy jenkins]

One common thread in virtually every skiing avalanche incident this season has been that the slab has not broken until the skier is well out on it and it has occured during attempts to "cut." The presence of recent natural avalanches should be a red flag waving in your face. It is good to be thinking about things like safety zones and escape routes, but don't let the competition for good lines allow you to get suckered onto these slabs. If you don't think that a 300# piece of cornice will mess you up, you might be in for a surprise.

Yea, just for the record, I knew the cornice was going to break, that was my means of assessing stability is because if a 300lb+ cornice dropping close to ten feet didn't make it slide, a 170lb skier making mellow turns probably wouldn't. I cut the cornice bit by bit with my pole ABOVE where I was dropping, so that I could drop just on the uphill edge of the uncut cornice, but not have to fight my way through anything as I made my way to the safe zone. I didn't want to drop where I had cut the cornice away, because without the cornice dropping, I didn't trust the slope. Not sure if that makes sense, but I cut and dropped in in a way that made sure the cornice dropped, but that also made sure that I was well away from it by the time the cornice actually hit the snow. The safe zone was also a much more pronounced flat area than it looks like in those pictures.

I wouldn't consider a ski cut as a reliable means of assessing stability (more of a just in case play it safe maneuver), but I would consider a decent sized cornice drop to be a pretty good indicator, if you can drop it safely. I would usually find a way to drop the cornice from above without stepping out on to it, but I wasn't able to get it to go except in small pieces, and I saw a way to drop it safely by skiing it, so I did. It's also just fun to drop cornices.

When I rolled up on this line there were already 20+ tracks on similar lines nearby Not a single skier had ski cut anything, and as far as I know, no one had dug a pit. After I kicked off the slide, several people went back up and skied on both sides of my line, actually right next to the snow that slid, without a ski cut or anything. My line was actually less wind loaded than most other lines, and if some of the other had slid they could have been twice as deep.

[pechelman]

Yea, just for the record, I knew the cornice was going to break, that was my means of assessing stability is because if a 300lb+ cornice dropping close to ten feet didn't make it slide, a 170lb skier making mellow turns probably wouldn't. .

key word highlighted

ive read a number of reports where control work was done with explosives and the slope slid on the 2nd or 3rd skier.

just an fyi for anyone else reading

[leroy jenkins]

key word highlighted

ive read a number of reports where control work was done with explosives and the slope slid on the 2nd or 3rd skier.

just an fyi for anyone else reading

Yea well, I guess we either accept the reality that it will never be completely safe to ski anything steep, and try and mitigate those risks, or just stick to the low angle stuff.

[JoeStrummer]

Yea well, I guess we either accept the reality that it will never be completely safe to ski anything steep, and try and mitigate those risks, or just stick to the low angle stuff.

Exactly!

I also think the line between those of us speculating on the interwebz from the warmth of our homes and those who got buried is much more slender than we would like to think.

[Smoove]

I've came up with a good way of cutting cornice that I thought might help. When I am backcountry skiing I usually carry a whippit. This tool is really helpful in cutting cornice that is not scarry big. I hold onto the basket and extend the whippit out the the cornice edge and then pull the whippet back towards me. This will create a channel. I make two channels 6 feet apart and three to four feet deep and preferably choose an area that is overhanging. I will then attach my thin rope I carry, that has knots every 6-8 inches, to the end of my pole. This way I can fish it out over the edge without exposing myself too much. Then get the rope in the channel and start sawing away. Sometimes it helps to clove hitch a small rock in the center of the rope so that it hangs further beneath the cornice. This creates an awesome bomb of the backcountry! It does take a little time, however it is a good test. It's also easier to saw with two people, one on each end. In skethy severly overhanging cornice it might be a good idea to be anchored and on belay as well.

Just some thoughts... The snow coverage looks surprisingly good..

[BackcountryBomb]

Hey Smoove, if you want to cut the larger, denser cornices, you might want to check out Lou Dawson's review of the Backcountry Bomb, a snow cornice cutting tool.

[AfroMullet]

Hey Smoove, if you want to cut the larger, denser cornices, you might want to check out Lou Dawson's review of the Backcountry Bomb, a snow cornice cutting tool.

get out.

[KillingCokes]

That thing looks sweet I think I'll put it on my XMas wish list

[powdork]

be careful cutting cornices (duh). sometimes you get more than you bargained for.

[leroy jenkins]

be careful cutting cornices (duh). sometimes you get more than you bargained for.

Maybe thats exactly what they thought was going to happen? Dropping that much cornice on something would be a great way to find out if you need to be worried of sympathetic releases, not to mention stability as a whole. As long as they were sure no one was below them, yee fucking ha.