Mount Helen (Montana)
Mount Helen () is located in the Lewis Range, Glacier National Park in the U.S. state of Montana. Mount Helen rises immediately to the northwest roughly above Upper Two Medicine Lake in the southeastern part of Glacier National Park. The Continental Divide of the Americas passes over the summit of Mount Helen. Geology. Like the mountains in Glacier National Park, Mt. Helen is composed of sedimentary rock laid down during the Precambrian to Jurassic periods. Formed in shallow seas, this sedimentary rock was initially uplifted beginning 170 million years ago when the Lewis Overthrust fault pushed an enormous  slab of precambrian rocks thick, wide and long over younger rock of the cretaceous period. Climate. Based on the Köppen climate classification, Mt. Helen is located in an alpine subarctic climate zone characterized by long, usually very cold winters, and short, cool to mild summers. Temperatures can drop below −10 °F with wind chill factors below −30 °F.