It towers dramatically over the south end of Ross Lake, rising 7,450 ft (2,270 m) above the lakeshore in only 3 horizontal miles (4.8 km).All are long routes with a great deal of vertical gain,[4] meaning most parties take three to four days to climb the mountain.The lower flanks of the mountain on the Ross lake side are composed of many different rock types including Orthogneiss, Ultramafic rock, low grade Phyllite, Tonalite, Continental glacier drift, Diorite, and Schist.Jack Mountain was created when the Hozameen Range was thrusted over the younger Harts Pass formation to the east.The lower flanks of the mountain to the west were created by the Ruby Creek Heterogeneous plutonic belt.