The earth evidently cycles in and out of Ice Ages with periods of warm weather in-between the cold. The earth is obviously in such a warm period now. Since multiple Ice Ages are historically documented for the earths past it is inevitable that in the future the earth will once again experience another Ice Age. There are two types of glaciers that can form. They are valley glaciers and ice caps.
Valley glaciers form in the mountain peaks and can flow downward and outward through the valleys.
Ice caps are large sheets of ice that can cover broad areas, as stated before, the size of whole continents. Movement of the ice occurs when a sufficient amount of ice thickness builds up. The weight of the overlying snow and ice forces the outer edges to move away from the center. This movement usually occurs after a thickness of about forty-five feet is obtained. Ice sheets of the Pleistocene Age were very large and covered whole continents.