Devils Postpile National Monument

Devils Postpile National Monument

Natural World

Nature & Science

Devils Postpile National Monument's landscape is a reflection of fire and ice. The eruption and uniform cooling of basalt lava created an impressive wall of columns. Later a glacial event exposed the columns and polished smooth the top of this formation enhancing the pattern of hexagons that are a result of the mineral composition of the lava. Located on the western slope of the Sierra Nevada range at 7,200 to 8,200 feet (2,200 to 2,500 meters), the 798 acres (320 hectares) is a small but rich environment.

Natural Features & Ecosystems

Devils Postpile National Monument was established because of two important geophysical features:  the postpile itself and RainbowFalls. The postpiles tower as a sheer wall of polygonal basalt columns up to 60 feet high, and glacial polish is evident on top of many of the columns.

Rainbow Falls is a spectacular waterfall that exists near the southern end of the monument on the San Joaquin River. The river changes in character many times throughout its journey through the monument, evolving along its course from a series of broad low-gradient meanders to scattered pools and fast-flowing rapids, cascades, and falls.

Environmental Factors

The vegetation and wildlife in the monument are adapted to periodic fire, and evidence of past fires can be found in charcoal and fire scars left on some trees. By dating fire events using tree-ring analysis or dendrochronology, one can develop a history of the frequency that fires burned through an area. While fire history studies have not been done for the Monument, fire history studies in similar forests in other areas of the Sierra Nevada have shown fires in lodgepole pine forests occurred an average of every 150 years and more frequently in lower elevation mixed conifer forests.


Devils Postpile National Monument's vegetation is a montane forest dominated by red fir and lodgepole pine. The monument's proximity to both west and east sides of the Sierra Nevada results in the presence of plants from diverse biological communities. Recent plant inventories documented 360 plant species in the relatively small 798-acre area of the monument.  Along the San Joaquin River and the few creeks that flow into it, typical montane riparian vegetation can be found, such as quaking aspen, black cottonwood, alder, and willows. Both wet and dry meadows dot the monument and during the spring and early summer when water is available, a colorful bouquet of wildflowers can be found.


In Devils Postpile National Monument, forests, meadows, and the middle fork of the San Joaquin River create a variety of habitats for animals. There are 135 vertebrates known for the Monument.

When visiting Devils Postpile, you may hear some of the wildlife before you see them, from the high warning squeal of the belding ground squirrel to the begging caw of the Stellar's jay. In the fading light of day, a mule deer or black bear may be found lingering in a meadow or along the river's edge.