Complex sentence: He left his flashlight with Olsen so that he could find him again, although even with this aid relocating the stranded survivor proved difficult, as this part of Bjørnøya is flat and there were no visual references to help orient the searchers.
Split into simpler sentences: He left his flashlight with Olsen so that he could find him again. Finding Olsen again proved difficult, as the part of Bjørnøya is flat and there were no visual references to help orient the searchers.