Winter at the Big Southern Butte in Idaho. Big Southern Butte is one of three rhyolitic domes near the center of the eastern Snake River Plain. The area supports lodgepole pine, aspen, Douglas fir, and manzanita (not common to this region). The butte is one of the largest volcanic domes in the world but at 300,000 years old is also one of the youngest. Hikers who trek to the 7,550-foot high summit are rewarded with spectacular panoramic views. Photo by James Neeley.