Photo Gallery: Extreme Ice Survey

This doughy-looking iceberg in western Greenland's Disko Bay was once part of the enormous Jakobshavn ice stream, a river of ice four miles (six kilometers) wide and several thousand feet thick.

The Extreme Ice Survey is focusing heavily on Jakobshavn, which in the past decade has retreated at about 120 feet (37 meters) per day, twice its normal rate.