Complex sentence: This desert is so arid that many mountains higher than are completely free of glaciers; indeed, only the highest peaks (such as Ojos del Salado, Pissis, and Llullaillaco) have some permanent snow coverage.
Split into simpler sentences: This desert is so arid that many mountains higher than are completely free of glaciers. Only the highest peaks (such as Ojos del Salado, Monte Pissis, and Llullaillaco) have some permanent snow coverage.