Why and how did continental glaciers form?

The size of a glacier (either a small valley glacier or a continental ice sheet) depends on what is called the mass balance, which is a measure of how much new mass enters the glacier through snowfall against how much leaves it due to melting. read more

Lower the temperature even further, and the glacier grows even more. Continental glaciers occur when you have so much ice staying that all the smaller glaciers start merging together to form progressively larger bodies of ice, until whole regions of continents are covered. read more

Continental glaciers are continuous masses of ice that are much larger than alpine glaciers. Small continental glaciers are called ice fields. Big continental glaciers are called ice sheets. Greenland and Antarctica are almost entirely covered with ice sheets that are up to 3500 m (11 500 ft) thick. read more