Glacial Change Documented

Although ice is generally thought of as rigid and immobile, glaciers are not stationary masses. In fact, in order to be considered a glacier, an ice mass must be of sufficient size and thickness to flow. Its sheer weight becomes so great that gravity forces the ice mass to spread outward and downslope.

When the amount of snow and ice accumulated on a glacier through precipitation or wind deposits exceeds the amount lost due to melting, wind erosion, or breaking off into the sea, it is said to have a positive mass balance year.

During extended warm periods, when the snow and ice lost over a year exceed what is gained, the mass balance is negative.

Accelerated melting of valley glaciers could produce catastrophic flooding followed by long-term drought, which would affect hundreds of millions of people who rely on stable glaciers to provide water for agriculture and their drinking supply.