Tuesday, July 15, 2008

Snow Anchor Options - Part I

Believe it or not, but you can use almost anything for a snow anchor.

There is a famous story about a female guide in the Alps who used a lighter as a deadman in the snow. She rappelled a steep couloir with the tiny object as her only protection. A few years ago on an Alpinism 1 course we buried a Powerbar, work hardened the snow, and then proceeded to clip a rope to a cord wrapped around the bar. Four people attached themselves to the rope and then bounced on it. The anchor held...for a few bounces. Eventually it blew out, but the force required to make it do so was tremendous.
While these unusual objects are not recommended, there are objects that we carry that are. A deadman is any buried item that might be used as an anchor point. Deadmen are often generated by commercial pickets and snow flukes. But there are many more options. Skis, trekking poles, packs, stuff-sacks filled with snow, and crampons are all items that we commonly carry that could easily be used as a deadman.

To make a deadman with an object that you would like to bury, first dig a T-slot. This is a hole that has been cut in the shape of a T. Second, girth-hitch or clove-hitch a sling around the object. The sling will run out of the body of the T. Place the object in the hole and then fill it in. After the T-slot is completely filled in, you must work-harden the snow on top of it. In other words, it must be packed down until it is completely flat and hard. Once this is complete, the object will have become a deadman anchor.
Another simple -- yet time-consuming -- snow anchor is the snow bollard. These are an excellent choice for an anchor that will be used for a rappel. To make a snow bollard, one must cut a teardrop shaped groove into the snow. One may then lay a rope into the groove and rappel. When bollards are cut correctly, they work better than anything else. When they are cut incorrectly there is a distinct possibility of failure.

All of these anchors should be considered suspect until they're tested. In order to test an anchor, back it up first. You may use a second deadman, an ice axe, a picket or a fluke to back-up the initial bollard. The back-up should be loosely linked to the line. Should the rope cut through the base of the bollard, the back-up will stop the anchor from failing completely.

Once the back-up has been established, the biggest individual with the largest pack should be sent down first. If the anchor holds the largest amount of weight available, then it's reasonable to assume that the anchor will continue to hold smaller individuals.

Snow anchors are an integral part of mountain climbing. In "Snow Anchor Options - Part II," we'll discuss more options and ideas for both simple and complex snow anchors.

More Information Online:
--Here is a short video on how to place an ice axe as a deadman. Ignore his use of the cord on the picket.
--Here is a short video on the use of a picket in a vertical placement.

AAI Courses that Cover this Information:
Glacier Skills and Crevasse Rescue
Alpinism I: Intro to Alpinism
Alpine Mountaineering and Technical Leadership: Part I
Sierra Intro to Mountaineering

--Jason D. Martin

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