Hubbard Glacier is the longest tidewater glacier in Alaska extending 76 miles from its source on Mt. Logan in the Yukon. The cliff face is over six miles wide, 300 to 400 feet from the top to sea level and 300 feet from sea level to the bottom. The Hubbard Glacier is a very active calving glacier , when the huge chunks of ice crash into the bay, it makes a thunder sound . I shot the photos of the glacier from the cruise ship Rotterdam Sept. 2010.