According to this map :
After crossing the Dyatlov Pass on January 31 they would ascend Otorten on February 1, then descend on February 2 and head east to Ilyich Base, reaching it between February 3 and 4, then turn back along the route they have already taken along Auspiya back to the pass, reaching it on February 6th, and then turn south.
What is this map based on? Am I misreading it? Did ILyich Base (Baza ILicha) even exist back in 1959?