Richmond Times-Dispatch Weekend - - INSIGHT -

Once glaciers be­come thick enough, they be­gin to move un­der their own weight. Pres­sure from grav­ity causes the glacier to spread out. This is called in­ter­nal de­for­ma­tion of the ice. Glaciers slide on a thin layer of wa­ter at their base. This wa­ter may come from glacial melt­ing due to the pres­sure of the over­ly­ing ice or from wa­ter that has flowed through cracks in the glacier. Glaciers can also slide over rocks and sed­i­ment.

Most glaciers move very slowly at only a few cen­time­ters a day. Some, how­ever, can move 160 feet a day and are known as gal­lop­ing glaciers.

The Ku­tiah Glacier in Pak­istan holds the record for the fastest glacial move­ment. In 1953, it moved more than 7.5 miles in three months, av­er­ag­ing about 367 feet per day.

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