Ice climbing is the activity of ascending inclined ice formations. Usually, ice climbing refers to roped and protected climbing of features such as icefalls, frozen waterfalls, and cliffs and rock slabs covered with ice refrozen from flows of water.
Generally, there are two kinds of ice climbing -- alpine and waterfall. As you might surmise from its name, you'll find alpine ice in a mountain environment. It's part of the terrain, may be steep or flat, is primarily derived from snow and is sometimes mixed with rock. Waterfall ice, on the other hand, is vertical, frozen water.