The [I 004 / glacier] is a frozen river flowing down a mountain slope. A glacier melts when it reaches lower altitudes. If each year it melts more than it grows, the glacier recedes. However, if it grows faster than it melts, it advances.
In its journey, a glacier scrapes away enormous amounts of material from the sides of its glacier-bank and from the bed of the valley through which it courses. This material forms a rocky ribbon called a [G 23 / moraine]. Rock areas on the side of the glacier are lateral moraines. Debris piles pushed along by the front end of the glacier are called terminal moraines.
