The Greenland and Antarctic ice caps are 2 miles thick. Alaska is four percent ice. The snowcapped Fairweather Range supplies ice to all glaciers on the peninsula seperating Glacier Bay form the Gulf of Alaska. In Johns Hopkins Inlet, several peaks rise from sea level to 6,520 feet within just 4 miles of shore. The great glaciers of the past carved these fjords, or drowned valleys, out of the mountains like great troughs.
Landslides help widen the troughs as the glaciers remove the bedrock support on upper slopes.
Huge icebergs may last a week or more. Colors betray a berg's nature or origin. White bergs hold many trapped air bubbles. Blue bergs are dense. Greenish-black bergs calved off of glacier bottoms.