Bear Glacier iceberg, Kenai Fjords National Park, 2012.

Bear Glacier calves some of the largest icebergs in the park. These massive chunks of ice fall into a lake just barely separated from tidewater by a wide, rocky beach. When huge chunks of ice break off a glacier (or other large ice mass) it may now be classified as a separate iceberg. Calving of glaciers is a natural process and often accompanied by a loud cracking or booming sound before blocks of ice crash into water below.