How Fast Do Glaciers Flow?
ES1507  Simulated Flag Movement

This animation shows the direction and relative speed of survey flags on the surface of Mathes Glacier projected over several years.

  !   Click the image to see the animation.
Foundation for Glacier and Environmental Research,
Juneau Icefield Research Program
Topographic map of Mathes Glacier area, Alaska. Contour interval is approx. 30 meters. Tan areas represent exposed rocks.

The simulated flow progresses smoothly, but the glacier's actual speed would vary. Glaciers move more quickly when temperatures are warmer. They also change speed in response to topography, speeding up as they move down steep areas.

5. Why do you think the center of the glacier moves faster than the sides?

6. Describe what the movement of the Mathes Glacier might feel like if you were camped in the middle of it.

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