A glacier is a large, continuous body of ice, formed when annual snowfall exceeds the amount that melts. This process takes many years, if not centuries. Glaciers slowly deform and ‘flow’ downhill due to its weight, carving wide U-shaped valleys into the terrain. Boulders and debris removed from the terrain by the movement of glaciers can be carried and deposited hundreds of miles away. Glaciers occur on land, not to be mistaken with sea that forms on bodies of water, and are located on every continent except Australia. In higher latitudes glaciers flow down to sea level, but in the tropics glaciers are only found on high mountain tops. It is estimated that one-third of the world’s population depends on glacial melt for their source of fresh water. Due to glaciers’ reliance on snow fall and temperature, glaciers are considered a sensitive indicator of climate change. Bainbridge Island’s topography was formed in large part by glaciers.