Why are the summer and winter routes different?

Winter routes to the huts often contain sections of cross-country travel where there are no underlying trails or roads, whereas summer routes follow established roads and trails. Winter snowpack makes off-road, off-trail travel more feasible. Obstacles such as water and dense vegetation can make winter routes impassable during the summer. Summer routes are not marked, however, they are indicated on summer maps produced by 10th Mountain. Winter routes are intermittently marked with blue diamonds, except in Wilderness Areas where they are intermittently marked with tree blazes.