Col, Welsh for saddle, is the low point on a ridge running between two peaks. The North Col (Camp 1) is 2,200' above ABC on Everest's North Ridge. This ridge runs from Everest's neighbor, Changtse, down to the North Col (21,300'), and ascends to meet Everest's Northeast Ridge at 27,500'.
To reach the North Col from ABC climbers hike about an hour up a gradual slope of rock and scree (loose gravel) to the head of the East Rongbuk Glacier. Here they strap on crampons. A half mile up the glacier the slope steepens, and the fixed ropes begin. The ropes zigzag from ice anchor to ice anchor up slopes of 35 to 60 degrees. Climbers clip their harnesses to the ropes with "ascenders", devices that lock on to the rope under load. They dig in with their crampons and work their way up, unclipping and reclipping at each anchor point of the rope. The climb takes 4 to 7 hours depending on the weather, physical condition of the climbers, and the load carried.
Tents, oxygen, rope, food and all other gear required for higher levels must be back packed up. Yaks, cooks, and support staff do not go beyond ABC. It takes several trips over a two weeks to move gear up. Air at 21,000'+ has less than half the oxygen of sea level air. Rest between trips is necessary.
