Hubbard Glacier is the longest tidewater glacier in Alaska extending 76 miles from its source on Mt. Logan in the Yukon. The cliff face you sail along is over six miles wide, 300 to 400 feet from the top to sea level and 300 feet from sea level to the bottom. As Hubbard is advancing, it creaks and groans as it moves and is a very actively calving glacier. This makes for some exciting moments when the huge chunks of ice crash into the Bay creating a wonderful sound called ‘white thunder’ by the Tlingit people.