The ropy surface of pahoehoe lava flows is the dominant lava type at Craters of the Moon. The pahoehoe flows were typically erupted through lava tubes and tube systems. Locally collapse of tube roofs has formed skylights and entrances to lava tunnels that are popular among visitors to the national monument.

Photo by Lee Siebert, 1994 (Smithsonian Institution).

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

Craters of the Moon