Complex sentence: During this solo climb Somervell made one of the most remarkable photographs in mountaineering history which shows Norton near his high point of where he tried to climb over steep sloppy icy terrain with some spots of fresh snow.
Split into simpler sentences: During this solo climb, Somervell took one of the most remarkable photographs in mountaineering history. It shows Norton near his high point of where he tried to climb over steep sloppy icy terrain with some spots of fresh snow.