The range forms a generally east-west arc with its northernmost part in the center, and from there trending southwest towards the Alaska Peninsula and the Aleutians, and trending southeast into the Pacific Coast Ranges. The mountains act as a high barrier to the flow of moist air from the Gulf of Alaska northwards, and thus has some of the harshest weather in the world. The heavy snowfall also contributes to a number of large glaciers, including the Cantwell, Castner, Black Rapids, Susitna, Yanert, Muldrow, Eldridge, Ruth, Tokositna, and Kahiltna Glaciers. Four major rivers cross the Range, including the Delta River, and Nenana River in the center of the range and the Nabesna and Chisana Rivers to the east.