So when you're climbing up hard windloaded slab, and you fall into a hidden slope-wide bergshrund/crevasse thingy, apparently the entire slope below the crack will release. I would have thought that the upper part, being steeper, would release too, but fortunately not. BTW this crust was skiable w/o incident beforehand.
_________________ Me llaman el desaparecido
que cuando llega ya se ha ido
volando vengo volando voy
de prisa de prisa rumbo perdido
Here's a few pictures from the recent slide cycle we had. Several of the slides were listed as hard slabs although the densities were slightly below 30%.
A little background. We had snow in the middle of October providing a good start to winter. Snow sat for a while and faceted with a couple of warm periods forming crust sandwiches. All that got buried but not enough to produce the widespread avalanching untill early December, when we got a lot of wind and some very heavy snow with 3-6 inches water weight added.
Layering causing the avalanche cycle is obvious in the photo taken about 10 days before the shit hit the fan.
A look at part of a crown triggered remotely from walking a ridge. The slide was about 1/4 of a mile wide.
A couple from another slide also remotely triggered from some distance away. The blocks are quite large as can be seen and are the reason behind calling many of the slides hard slabs.
The view of the slide from the next drainage over. Not that big but stress fractures run across the entire slope.
Yet another slide in a different area. The angle eases off quickly and trees below provide anchoring so the giant block just slid down the hill a little ways but the majority of the slide ran over a thousand vertical.
The devastation left after another slide in the drainage just west of the previous picture. This slide was over 1/4 mile, biggest one I'd seen in that area, took out big trees and ran over a thousand vertical. The slide path can be seen in the bottom of the picture and jumped the ridge seen also producing more avalanching in the next one.
One of those is about all a person can take in a winter. The cycle wasn't user friendly and we lost a skier, two snowshoers and a snowmobiler, all buried in a two day period.
Joined: Sat Nov 13, 2004 11:31 am Posts: 218 Location: ak
Wow, those are some spooky avy pics!
I don't recall ever seeing any pics that intense before. We've had some tender snow, but you're breakin some serious snowpack there. Musta been pretty wild hiking around out in the woods. Huge fractures, the whole ridge half peeled away.
I was just wondering how steep the slope on the 3rd and 4th pic is? Seems pretty plane, but maybe its just the perspective.
Slope angle on the slide in the third and fourth pics is right around 35 degrees. I actually triggered it remotely the previous day when the hazard was rated high to extreme and didn't discover the slide until the next day when I repeated the route as the visiblilty was better and for taking pictures of the damage. The stress fractures radiated out from the slide over to the shot I'd done where the angle of the slope was around 30 degrees.
The pictures are from the Wasatch in Utah and are of a slide cycle beginning on the 8th of December and lasting a couple more days with the last avalanches of the cycle explosively triggered on about the 12th.
Usually see something like that once a winter, since snow falls early and then rots, producing the weak layers, then a good storm cleans things out as it did this time and we can just worry about new snow instabilities. The cycle this year was about a month early and similar weak layering is occuring now as we haven't had a good snowfall for a while. Could see a repeat of the cycle with another good sized storm.
The explosives were used not by me, but by the heli ski operation for "stability testing" after a heavy snowfall on a persistent weak layer.
I just documented the slide cycle after it occured.
It was controversial and there are discussions between a number of interested parties about the damage done and whether it should be continued in that fashion in the future.