Of the several types of glaciers, those called Tidewater Glaciers have their terminus at the sea. If the glacier is fed by enough snow to flow out of the mountains, ice will break off or calve into water at sea level, leaving blocks of ice floating in the water.
The Prince William Sound is home to more tidewater glaciers than any other region in Alaska, with approximately 20 glaciers flowing into the ocean. Hundreds of other glaciers cap the surrounding mountains and fill the valleys around the Sound.
Photo © copyright by Dr. Edward Mikol.