peak in Washington. It stood out prominently from surrounding hills because of the symmetry and extensive snow and ice cover of the pre-1980 summit cone, earning it the nickname, by some, "Fuji-san of America". The peak rose more than above its base, where the lower flanks merge with adjacent ridges. The mountain is across at its base, which is at an elevation of on the northeastern side and elsewhere. At the pre-eruption tree line, the width of the cone was . Streams that originate on the volcano enter three main river systems: The Toutle River on the north and northwest, the Kalama River on the west, and the Lewis River on the south and east. The streams are fed by abundant rain and snow. The average annual rainfall is , and the snowpack on the mountain's upper slopes can reach . The Lewis River is impounded by three dams for hydroelectric power generation. The southern and eastern sides of the volcano drain into an upstream impoundment, the Swift Reservoir, which is directly south of the volcano's peak. Although Mount St. Helens is in Skamania County, Washington, access routes to the mountain run through Cowlitz County to the west, and Lewis County to the north. State Route 504, locally known as the Spirit Lake Memorial Highway, connects with Interstate 5 at Exit 49, to the west of the mountain. That north–south highway skirts the low-lying cities of Castle Rock, Longview and Kelso along the Cowlitz River, and passes through the Vancouver, Washington–Portland, Oregon metropolitan area less than to the southwest. The community nearest the volcano is Cougar, Washington, in the Lewis River valley south-southwest of the peak. Gifford Pinchot National Forest surrounds Mount St. Helens. Crater Glacier and other new rock glaciers During the winter of 1980–1981, a new glacier appeared. Now officially named Crater Glacier, it was formerly known as the Tulutson Glacier. Shadowed by the crater walls and fed by heavy snowfall and repeated snow avalanches, it grew rapidly ( per year in thickness). By 2004, it covered about , and was divided by the dome into a western and eastern lobe. Typically, by late summer, the glacier looks dark from rockfall from the crater walls and ash from eruptions. As of 2006, the ice had an average thickness of and a maximum of , nearly as deep as the much older and larger Carbon Glacier of Mount Rainier.