Science
How does a glacier work?
A glacier works as a slow-moving river of ice, formed where snow piles up faster than it melts and compresses into dense ice over centuries. Its own enormous weight makes it flow downhill, carving valleys and shaping landscapes.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a glacier works.
Step by step
- 1Snow accumulates and compresses into thick, dense ice over time.
- 2Once heavy enough, the ice slowly flows downhill under its own weight.
- 3It grinds and carves the land, sculpting valleys and ridges.
- 4It advances or retreats as snowfall and melting change.
- 5Glaciers store much of Earth's fresh water and are shrinking with warming.
Frequently asked questions
- How does a glacier move?
- Its huge weight makes the ice deform and slide slowly downhill, sometimes lubricated by meltwater at its base.
- How is a glacier formed?
- Where more snow falls than melts each year, layers build up and compress over decades to centuries into dense glacial ice.
- Why are glaciers important?
- They hold a large share of the planet's fresh water and feed rivers; their rapid melting from warming raises sea levels.