Glacial retreat continues today on the bay's east and southwest sides, but on its west side several glaciers are advancing. The snowcapped Fairweather Range supplies ice to all glaciers on the peninsula separating Glacier Bay from the Gulf of Alaska. Mount Fairweather, the range's highest peak, stands at 15,320 feet. Near 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 moutains 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, and they provide perches for bald eagles, cormorants, and gulls. Colors betray a berg's nature or origin. White bergs hold many trapped air bubbles. Blue bergs are dense. Greenish-blackish bergs may have calved off glacier bottoms.