The McKenzie Pass area contains one of the largest concentrations of recent volcanism in the continental United States. Fresh lava flows in the foreground from the Belknap shield volcano merge with unvegetated lava flows from scoria cones on the north flank of North Sister in the background, with Middle Sister to its right.

Photo by Lee Siebert, 1982 (Smithsonian Institution).

This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.

Keywords: stratovolcano | lava flow

Three Sisters