Panum Crater

This is probably one of my favorite hikes ever, and a very unique one. Where else do you get to walk all the way around and into a semi-​active volcano in California? Joe R. does a fantastic job of describing the trails. To actually get to the trailhead, you have to take Highway 120 from 395, then turn onto a dirt and gravel road to your left. There’s several of these unnamed but defined paths, and a small brown sign identifies the way to Panum Crater. It’s pretty easy to miss, but all those rocky roads eventually intersect. It just won’t be a pleasant experience for you or your car.
The trailhead contains some informational boards on the geological formation of Panum Crater, and the Mono Lake Committee holds guided walks during the summer (
). We were maybe about 5 minutes into our Rim Trail walk when we realized all the little shiny flakes on the ground were obsidian, and our competition to see who could find the biggest piece was effectively rendered moot when we took the Plug Trail up and saw we had been standing on dino-​sized slabs of it the whole time. Keep in mind this is not a gift shop though, and leave everything you find!
Both trails are pretty easy but do involve a lot of ups and downs with no shade in high altitude, so definitely bring hats, sunglasses, water, etc. The trail consists of all loose rocks and sand that love to get in your shoes and socks. But walking around the rim and seeing Mono Lake, the crater, and the rim itself is spectacular. In the plug, there’s lots of opportunities to clamber around on the natural rock towers for an even better view.

The best way to study geology is to explore the earth, and climb around on its landforms. For a lesson in volcanology, we visited Panum Crater, a textbook example of a complete plug dome volcano, located near the south shore of Mono Lake. The volcano erupted in the 14^th century, and consists of a central lava dome surrounded by an intact ring of ejecta. To encouter the geology, we followed two accessible and easy trails, one circumnavigating the rim of the volcano, and the other traversing the crater and plug dome.
The undulating, two-​mile Rim Trail completely encircles the volcano, follows the crown of the ejecta ring, and includes a magnificent panoramic view of Mono Lake. Since the trail surface consists of loose sand– and gravel-​sized rock blown out of the volcanic crater, the footing is soft and sluggish, like along the crest of a sand dune. The high point of the Rim Trail is at the north end, where a 180-​degree vista of Mono Lake unfolds.
The shorter Plug Trail ascends the lava dome in the center of the volcano. The lava dome consists of huge mounds of black volcanic glass (obsidian) and airy beige pumice. Much of the obsidian and pumice are banded together as the frothy pumice floated atop the rapidly cooling lava, like the foam on a pint of Guiness stout.
Thirsty for knowledge, we found Panum Crater an enlightening chapter in the textbook of geologic wonders of eastern California. In my book, it gets 4 stars for its out-​of-​this-​world scenery, birds-​eye view, stimulating trails, and textbook geology.

On my little weekend road trip from Yosemite to home in the OC, the Panum crater was by far the most unique place I visited. I have a an affinity for geologic formations and this plugged ancient crater is incredible. The hike is easy, a bit challenging as your walking upslope in gravel around the rim, and then you dip into and on to the lava plug. Huge boulders of obsidian striated with other volcanic glass is littered everywhere. Black and red pumice chunks mimic the tufa structures in Mono Lake below. It is recommended to come here in the early morning or afternoon as it can be hot and the shadows make this quiet place seem a bit more ominous.