Richard Cautley of the Interprovincial Boundary Survey wrote of the pass, "Fortress Pass is in several respects extraordinary. Travelling up the open gravel beds of the Chaba River, with its wide, straight and well-drained valley, stretching for miles to the south and ending in a mighty glacier, Fortress Pass appears as a small, timbered flat on one's right, without in any way suggesting the idea of a mountain pass. The Chaba River at this point is still a big river, with gravel beds from 700 to 1300 feet wide and numerous water channels.