How Fast Do Glaciers Flow?
ES1507  Flowing Ice

Valley glaciers have been called "rivers of ice." Images like this make it easy to visualize that the ice is moving downhill under the force of gravity. Though glacial ice is solid, these thick masses of compressed snow and ice behave like a very viscous fluid, moving slowly downhill.

Z. Smith
Kennicott and Root Glaciers, Alaska

If you were to watch a valley glacier for several hours, or if you just were to look at it every day for several weeks, it would be hard to tell that it was moving. However, flow rates for glaciers are very commonly measured and reported.

1. How could you measure the speed at which a glacier flows?

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