The Rockies were formed from 80 million to 55 million years ago when Pacific plates started to slide under the North American plate forming a ridge of mountains along western North America. Millions of years of erosion and glacial activity have left behind a dramatic and beautiful landscape. The highest point in the Rockies is Mount Elbert in Colorado at 4,400m (14,440 ft). The highest mountain in the Canadian Rockies is Mt. Robson in British Columbia approx. 1 hour west of Jasper. Mt. Robson is 3,954 m (12,972 ft) high. The Rockies range from 110 km (70 miles) to 480 km (300 miles) wide. The Continental Divide runs through the Rockies. Snow melt on the west side of the Divide flows to the Pacific while snow melt on the east side flows, eventually, to the Atlantic. There are areas where the snow melt also flows north to the Arctic Ocean.