JoshK Posted March 15, 2003 Posted March 15, 2003 Shot 8 at alpental is always a perfect example of this. It starts to develope creep cracks and if you are lucky enough to big around when it goes, well...it goes big. Quote
leejams Posted March 16, 2003 Posted March 16, 2003 Mattp, actually you probably can find those creep cracks any time of the year. It will all depend on the weather pattern's. Example was back a month or so on whitehorse we found many of those creep cracks and rather annoying to step across. On the other hand you are exactly right about spring conditions as this was the middle of winter with spring conditions. Quote
To_The_Top Posted March 16, 2003 Posted March 16, 2003 Do you mean shooting cracks as you were walking on it, meaning they opened across the slope that as you were on it(run the other way!) or cracks in the snow that were already there? Joshk, where is shot 8? Which side of Alpental? TTT Quote
JoshK Posted March 16, 2003 Posted March 16, 2003 TTT, as you get on the quad chair, about 30 seconds look up to your left. Above the forest and out of bounds zone there is a pretty obvious face/slab/something high up. It's pretty much the only non-treed area on that ridge to the left of the chair. I hear it gets skied every once in a great while, and you'll get arrested if you get caught. Â Disclaimer: I *think* the name is shot 8. I may have my shots mixed up. Tequila, vodka, it's all the same. Quote
ski_photomatt Posted March 17, 2003 Posted March 17, 2003 Dru, getting back to something you said, I'm assuming the cracks really existed and trying to explain them, not trying to show that the post was BS. Â I've been thinking about this over the weekend and discussing it with some other skiers. It's led me to rethink through the mechanisms of how cracks form in the snowpack and what holds different types of slabs together so even if a suitable answer isn't reached, I feel like I've at least learned something The consenus was that wet saturated slush can't crack like this, at least not on its own above a crust like a dry, hard slab can. Something else was happening. Perhaps it was a glide crack or it was a very deep and severe settlement far below any recent snow. This seems possible given the amount of rain and warm temps. Finally, it seems at least conceivable that given the strong winds last week something funky with temperature, wind and a localized terrain feature created a snowpack different than a foot of slush. The sensor at alpental was above freezing at both the parking lot and 4300 ft every hour from Sunday through Thursday, but at times it was near 34 or 35. I dunno, a couple of degrees colder and wind driven rain creates a hard slab before the rain can filter down. Who knows. Not me, that's certain. Â I was out skiing Sunday. It was crap, but I did take the time to dig 2-3 feet down. The snow pack at 5000ft was completely saturated for the first two feet, with all the recent snow compressed to a foot or so above a crust. There was another, less distinct crust another foot down, below it looked a little less saturated, certainly still wet, but I honestly didn't take the time to seriously look. I did see a fair amount of glide cracks, even was surprised to have to ski over a few small ones in steeper places. The snowpack frankly looked very sad, although it was snowing hard at 4pm up high, 1-2" had accumulated in a half hour or so. Quote
Geek_the_Greek Posted March 17, 2003 Posted March 17, 2003 Sounds like a consensus is developing that it was glide cracks out there - the whole shebang sliding off the rocks and moss due to excessive saturation of the whole snowpack. Maybe no more skiing at low elev's this year... Quote
JoshK Posted March 18, 2003 Posted March 18, 2003 Well, glide cracks will generally develop on certain types of terrain and slope angles. I dont see them often on 30 slopes, nor on slopes with decent tree anchors. I would agree that 45 degree slops over slabs is where you'd find the most danger, esp. when they result in climax avys, where the entire fuggin' thing lets go down to the ground. Quote
AlpinistAndrew Posted March 18, 2003 Author Posted March 18, 2003 sorry for any confusion on the "cracks". i am not an avalanche expert. my partner and i just knew that whatever it was, it probably wasn't good. Quote
Dru Posted March 18, 2003 Posted March 18, 2003 werre the cracks already present and you just saw them, or did they suddenly appear and propagate as you walked on the snow, aa? Quote
JoshK Posted March 18, 2003 Posted March 18, 2003 AlpinistAndrew said: sorry for any confusion on the "cracks". i am not an avalanche expert. my partner and i just knew that whatever it was, it probably wasn't good. Â No worries. You did the right thing. I've always taken that same approcah. If it looks scary, and I don't know how to explain it, I'm going somewhere else... Quote
AlpinistAndrew Posted March 18, 2003 Author Posted March 18, 2003 The cracks were already there. Quote
Dru Posted March 18, 2003 Posted March 18, 2003 then i agree it was most likely snow glide of saturated snow pack. by the way this exerts enormous tractive forces - a friend did her M. Sc on this phenomenon on the slabs at the base of Yak Pk and found forces well in exceedance of the shear force of a bolt, in fact the station her data logger was fixed to was pulled out of the rock (4 fixe 3" bolts anf hangers) and carried 10 downhill, by snowglide. Â when you said "shooting cracks" i thought you meant cracks propagating out from where you stepped which is a BAD THING to see Quote
snoboy Posted March 18, 2003 Posted March 18, 2003 Dru said:when you said "shooting cracks" i thought you meant cracks propagating out from where you stepped which is a BAD THING to see  Actually, dru, the scientific term would be "VERY BAD THING!!!" Quote
Cpt.Caveman Posted March 18, 2003 Posted March 18, 2003 shooting cracks means - go the fuck away unless you dont care. Quote
ski_photomatt Posted March 19, 2003 Posted March 19, 2003 I interpreted 'shooting cracks' to means cracks shooting away when you stepped too. Usually glide cracks imply stability but you still need to be careful. They tend to have areas nearby that aren't super sound like crevasses and you could fall into the hole they create , be standing on top of a huge slab when it decides to let loose, , or get buried from above when one goes Quote
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