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Crevasse Safety and Mental llusions

Any time we travel to a new area, we take a series of precautions to avoid crevasses. First, we look at high-resolution radar and visible light satellite images that show many of the crevasses and select the clearest route. When we travel over new terrain, we use Ground Penetrating Radar (GPR), which images the shallow ice and allows us to see crevasses within a certain distance. The most challenging precaution that we take is traveling with roped skidoos. This means we connect all the skidoos and sleds with thick ropes, and each person wears a mountaineering harness connected with a climbing rope to the sled or skidoo ahead or behind. Having the skidoos connected means that we have to carefully coordinate driving so we all drive together at the same speed, and we need to travel slowly so the person watching the GPR output can stop the group quickly if they see indications of a crevasse. The final precaution is to watch the snow for surface changes that could indicate a crevasse covered with a snow bridge. Once a safe route has been established this way, we no longer need to take as many precautions and can unrope the skidoos and travel faster. On an established route, we typically travel at 15-25 km/hr. Because the snow surface forms into small “snow dunes” called sastrugi, the irregular surface makes it dangerous to travel much faster than about 25 km/hr.

Because of the clean white snow surface, it’s very easy to spot even small objects on the snow (except when they’re white, which means you can spend hours searching for them). In the endless white expanse, even the smallest fleck draws the eye, and we have frequently stopped on our skidoo trips to pick up a stray candy wrapper or other small object winking out of the snow. Even a piece of dirty snow from the skidoos initially seems like it could be something interesting, but disappoints on approach.

I also frequently catch myself thinking at a glimpse that I see animals or birds, though I know there are none here. Sometimes I’ve turned my head quickly and wondered if the small, dark object I saw out of the corner of my eye was a mouse scuttling by, only to remember that there are no animals here, and it’s only a clump of tape or a piece of dirty ice. At other times, I look up at the sky, thinking subconsciously I might see a bird or plane, only to remember that the sky is always empty, only clouds and occasional ice crystals.

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One Response »

  1. hi nadine
    Sounds really interesting. Hope your having fun! Keep us posted.