The wave of ice may move at two to six times the velocity of surrounding thinner ice. A lahar is a mudflow or debris flow originating on a volcano. A moraine formed at the side of a glacier. Piles of loose unsorted rocks along the side margins of the glacier. The rocks may be pushed there by the moving ice or dumped from the glacier's rounded surface.
Mass balance describes the net gain or loss of snow and ice through a given year.
It is usually expressed in terms of water gain or loss. They appear as dark streaks of rock along the glacier centerline. Rock debris deposited by a glacier. Neoglaciation refers to the advances made by mountain glaciers since the great Pleistocene ice age. In the Cascades the advances have occurred since 6,600 years before present.