The bottom of a glacier is always in motion , albeit with a very slow, river-like movement.
Glaciers occur when snow accumulates, compacts, and crystallizes. Most are found in areas near the poles, which is where annual snowfall exceeds evaporation in summer. One of the most curious aspects of glaciers is in the amount of fresh water they accumulate: more than 75% of the total amount in the world!
The process of growth and establishment of a glacier is known by the name of glaciation. At present, our planet faces the problem of the great melting of glaciers, which lately exceeds crystallization, that is, they occur at such high speed that they do not allow time for the ice sheets to recover.





