Stock Photo of a D7 Tractor Moving a Geophysical Camp Over a Break in Sea Ice
After building a snow bridge to disperse weight, housing and equipment trailers are towed safely over a crack in the sea ice. Geophysical crews work during the arctic winter when they can travel out onto the ice of the Beafort Sea, north of the coast of Alaska. Photo taken in 1980 of a D7 Caterpillar tractor moving trailers, which are on Ski's.

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