The colorful Painted Dunes at Cinder Cone in NE Lassen Volcanic National Park were formed when ash deposits from Cinder Cone were oxidized by a still-hot underlying lava flow. The mounded surface of the ash reflects the irregular topography of the underlying Painted Dunes lava flow. A black ash-free lava flow, also erupted from Cinder Cone at a later date during the same eruption, can be seen at the top of the photo.

Photo by Lee Siebert, 1998 (Smithsonian Institution).

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

Lassen Volcanic Center