چرا برخی از یخچال های صخره ای آلاسکا در سراشیبی مسابقه می دهند در حالی که همسایگان آنها به سختی حرکت می کنند

Why some Alaskan rock glaciers race downhill while their neighbors barely move

Two massive rock glaciers are creeping down mountain valleys in Alaska's Wrangell–St. Elias National Park. They sit only a few miles apart and formed under the same sky. One moves more than 5 feet (1.5 meters) a year. The other moves at less than half that pace.