Ubehebe Crater is part of a volcanic field that includes a number of basaltic cinder cones, and seven or so phreatic (groundwater) explosion pits called maars. The volcanoes are quite young, with some that erupted as recently as 800 or so years ago (though the dates are still being debated). The biggest crater is 750 feet deep and half a mile across. The groundwater explosions were caused when magma approached the surface, heating the water and causing it to flash to steam. Dozens of explosions would have accompanied the formation of each crater.
The craters are a fascinating destination for Death Valley travelers, although few make the effort unless they are also going to Scotty's Castle. Walking to the bottom of the crater is one way to gain an appreciation for the power of exploding magma. So is a walk around the biggest crater. In the picture above, the cars in the parking lot on the opposite rim are barely visible.
But the reason I love stopping in at Ubehebe is the sense at being at the edge of the wilderness. The pavement ends, and only gravel roads continue, towards Racetrack Playa in one direction, and the distant town of Big Pine in the other. The lands seen from the edge of the crater rim feel like terra incognita. It's wild, lonely country.
The fourth day of our recent journey to Death Valley was devoted to an exploration of the north end of Death Valley, with stops at Bonnie Claire Playa and Ubehebe. The day was ending as we drove back down the valley towards Stovepipe Wells, but the sky was gorgeous.