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 four 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, and they provide perches for bald eagles, cormorants, and gulls. Blue bergs are dense. Greenish-blackish bergs may have calved off glacier bottoms. Dark-striped brown bergs carry morainal rubble from the joining of tributary glaciers or other sources. How high a berg floats depends upon its size, the ice's density, and the water's density.