Three Sisters Volcanoes

The Three Sisters areas is located in the Central Oregon High Cascades. This is part of the Cascade Range which extends from northern California to northern Washington (USGS, 2002a). The area has a temperate maritime climate and the mountains act as major barriers, intercepting eastward-flowing moisture (USGS, 2002d). As a result, there are warm, dry summers and higher precipitation in the winter. Areas of higher elevation, like the Three Sisters, receive most of their precipitation as snowfall.