The ice in the middle of a glacier flows faster than the ice along the sides of the glacier.

Three conditions are necessary to form a glacier: (1) Cold local climate (polar latitudes or high elevation). (2) snow must be abundant; more snow must fall than melts, and (3) snow must not be removed by avalanches or wind.

It is in the metamorphic process of snow-becoming-ice. Eventually, firn changes into solid glacier ice. Firn takes about a year to form. (In colder parts of the world, this could take as long as 100 years.)

Glacier ice is blue because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered.

When the lower ice of a glacier flows, it moves the upper ice along with it, so although it might seem from the stress patterns (red numbers and red arrows) shown in Figure 16.13 that the lower part moves the most, in fact while the lower part deforms (and flows) and the upper part doesn’t deform at all, the upper part …

The slowest glaciers in the world are cold-based glaciers, which often only move very slowly. These glaciers are frozen to their bed and have little basal sliding. The velocity and flow of a glacier is mostly controlled by its thermal regime.

Antarctic Ice Sheet

The people who travel to or live in Antarctica fall into two main groups, those who live and work on scientific research stations or bases, and tourists. No-one lives in Antarctica indefinitely in the way that they do in the rest of the world. It has no commercial industries, no towns or cities, no permanent residents.