Glacier. Wall of ice consisting of frozen pillars of water standing upright, are seen on Mount Kilimanjaro, the highest (5900m) mountain in Africa. A glacier is usually a frozen river of ice moving down a valley, but the term is now also applied to a mass of snow and ice falling on high ground, compacting, and then moving outward and downward towards the sea. An ice-face or cliff, such as this, usually forms at the sides of the glacier by the shearing action of the valley sides as the ice moves along. An ice-face also usually forms at the front of the glacier.