1. "The great curving ramparts of the Bala Hisar Fort loomed over the receding town, glowing in the fiery light like a long-dormant volcano on the verge of awakening" (157; ch. 13). It's a simile, because it uses "like" to compare the color of the rampart to the color of lava.
"... Mortenson lay awake much of the second night, test-driving and rejecting various strategies" (166; ch. 13). It's a metaphor, because he is comparing the trial and error of different plans to trying out vehicles.
"the rising sun iced the hanging glaciers of Masherbrum pale pink, like a gargantuan pastry dangling above them at breakfast time..." (206; ch. 16). It's a metaphor, because it compares the color of the mountains to that of a pastry.
1. rampart (157; ch. 13): n. a fortification.
2. phlegm (162; ch. 13): n. thick mucous.