What exactly are glaciers?
Glaciers are massive ice bodies that form from compacted snow and persist year-round, both in summer and winter. Due to their enormous weight and gravitation, these ice masses flow slowly from the mountains toward the valleys.
The glaciers move in different ways:
- Plastic deformation: The ice deforms under the high pressure of its own weight, which can lead to folding and crevasses in the ice.
- Basal sliding: At the glacier base, a layer of liquid water acts as a lubricant, allowing the glacier to slide over the underlying surface.
- Subsurface deformation: If a glacier is on soft substrate, this can also deform under pressure and contribute to movement.
The speed at which glaciers flow varies widely. Alpine glaciers typically flow at rates of 10–200 meters per year, with larger glaciers moving faster. Glaciers can be several kilometers thick and hundreds of kilometers long. The largest glaciers in the world are in Antarctica and Greenland, but significant glaciers can also be found in the Andes and the Alps.
Did you know that 10% of the Earth’s land surface is currently covered by glacial ice and that around 70% of the world’s fresh water is stored in glaciers?