Glac

Glac (plural glacs) is not a formal term in standard scientific nomenclature. In some field guides, teaching materials, and informal glossaries, glac is used as shorthand for glacier or glacial phenomena. Because usage varies by author and language, it should be defined locally when encountered, and it is generally avoided in formal publications.

A glacier is a large, persistent mass of ice that forms from the accumulation and compaction of snow over many years and flows under its own weight. Glacial ice erodes and shapes landscapes through abrasion and plucking, and it transports rock debris within the ice to form moraines. Glaciers have accumulation zones where snowfall adds to the ice, and ablation zones where melting and sublimation remove ice. Surface features include crevasses and seracs, while the lower edge is called the terminus.

Glaciers occur on every continent except Australia, with the majority stored in Greenland and Antarctica. Mountain glaciers are found in ranges such as the Alps, Andes, Himalayas, Rockies, and the Caucasus. They supply freshwater during melt seasons and create landscapes such as U-shaped valleys, cirques, and fjords.

In climate science, glaciers serve as indicators of climate change. Many glaciers have retreated and thinned in recent decades, contributing to sea level rise and affecting regional water resources. Scientists monitor glaciers using field surveys, satellite imagery, radar and lidar, and mass-balance measurements to understand their response to temperature and precipitation changes.