How Fast Is Glacier Flow?

Most glaciers creep at 10-300 metres per year. Over very long spans they carve fjords, transport boulders hundreds of kilometres, and reshape continents. Greenland's Jakobshavn Isbræ is one of the fastest, sometimes flowing 46 metres per day.

Glaciers preserve ancient ice — Antarctic ice cores contain trapped air bubbles from very long ago, giving direct samples of past atmospheres.

• 1,000× faster than tectonic plates drift
• Still roughly a million× slower than walking