Discover the Wonders of Our Earth and the forces and life forms that shape our world with the Physical Geography Series. Present day glaciers have considerable economic importance in many areas. In the Western United States glaciers are considered to be frozen reservoirs which release water during the warmer summer months. They are also of considerable importance to the irrigation of crops and hydroelectric power and to feeding underground water reservoirs. For this reason scientists have been studying glaciers around the world. Explore how glaciologists are using new scientific tools to study glaciers on the surface of the earth. See how satellites keep track of glacial growth or shrinkage in places like Antarctica, Greenland and Iceland.