26 Sep Postpile Ridge
While not as distinctly formed as Devils Postpile National Monument, this thousand-foot long ridge, located high above Storey County’s Long Valley Creek, is still an impressive sight. About a three-mile walk from the entry to the canyon near the town of Lockwood, the hike to the ridge involves frequent crossings of the (mostly) shallow creek, and culminates after another three miles at the spectacular petroglyphs of Lagomarsino Canyon.
Click here to see the location in a satellite view.
These basaltic columns form when a mass of pooled lava cools slowly and evenly. As the lava cools, contraction occurs, and the rock fractures in a similar way to drying mud, with the cracks propagating down as the mass cools, leaving the pillar-like structures. This process is explained here. If the lava had cooled perfectly evenly, all of the columns would be expected to be hexagonal, as seen at the Giant’s Causeway in Ireland.