The route crossed a pass 3,439 m ( 11,283 ft ) high , just over 20 km west of modern Parachinar , that was blocked by snow for several months of the year .
The Kurram River crosses the Afghan-Pakistan border about 80 km southwest of Jalalabad and in ancient times offered the most direct route to Kabul and Gardez , but the route crossed the Peiwar Pass 3,439 m ( 11,283 ft ) high , just over 20 km west of Parachinar , which was blocked by snow for several months of the year .