Subway Cave Interpretive Trail, California - Self Guided Walks and Trails on Waymarking.com

Subway Cave is a section of lava tube about a third of a mile long, located between two areas of ceiling cave-ins. Large concrete steps have been constructed at both ends of the cave, providing easy access. The entrance is known as the Devil’s Doorway (N 40° 41.164' W 121° 25.135') and the exit is known as Rattlesnake Collapse (N 40° 41.060' W 121° 25.045').

Cave is accessed from the Subway Cave Trailhead which provides parking, picnic tables, toilets, and drinking water. There are interpretive signs along the short access trail and inside the cave.

Signs at trailhead
Hat Creek Lava Flow - Rivers of Molten Rock - Lava began spewing from deep cracks in the earth some 30,000 years ago. Rivers of molten, red hot rock crawled northward 16 miles, covering the floor of Hat Creek Valley. While the top crust cooled and hardened, rivers of red-hot lava insulated by the newly formed rock above, continued to flow. Eventually, the lava drained away, leaving tube-like caves. Subway cave is the largest accessible tube in the flow.
Map of Subway Cave - Welcome to Subway Cave! This easy 1/3 mile walk will lead you through the underground world of a lava tube. It begins and ends at the parking area. Take a good light (or two), a jacket, and follow the interpretive signs for a self-guiding tour.

Signs along trail
Subway Cave Trail - Welcome to Subway Cave Trail. This trail is an easy 1/3 mile walk which begins and ends at the parking lot. Along the trail you will visit the underground world of a lava tube. Subway Cave was originally discovered by the Atsugewi (Hat Creek) Indians, but as far as is known, they made no use of it. They belived that the cave was inhabited by an evil creature best described as an ape man.
Molten Lava River - About 2000 years ago (OLD INFO - NEW DATING PLACES ERUPTION AT ABOUT 24,000 YEARS), a crack opened in the valley floor two miles from here toward Lassen Peak. From this “fissure” flowed a river of red hot molten lava. The lava ran down the valley floor toward the spot where you are standing. As it flowed, it began to cool and thicken like warm fudge. Individual fingers of the solf material oozed out from the main flow and were frozen into rounded edges of rock by the cool air. You are standing on top of one of these ridges. But almost as if this ridge were the burrow of a giant mole, it is hollow inside.

Inside Cave
Stubtoe Hall - Watch your step. The floor here is very rough. As the hot lava drained out of the hardened shell, a froth was left behind on the cave floor. The jagged stones imbedded in the froth are a form of pumice that was carried along with the lava.
Windtunnel - This portion of the cave gets its name from the slight breeze that you may be able to feel on your cheek. On the walls you can see the marks lefts behind by two separate lava flows that passed through the caves. The first flow left a thin “high water” mark on the wall about 12 inches from the roof. In the second flow the lava was cooler and left the more chunky line about three feet from the floor. Take the fork to the left at the end of the windtunnel. CAUTION: The door is rough and the ceiling is low.
Lucifer’s Cul-de-Sac - Some times short fingers of lava branched out from the main flow. This chamber was formed when the side stream of lava halted and returned to the main flow. Look at the long ridges on the floor. They are probably pressure ridges caused by compression of the lava floor. Flash your light to the ceiling. Do you see any sparkles? Often the ceiling is covered with tiny drops of water which gleam like little jewels in the lantern light; this is percolating ground water, and the amount varies with the moisture in the ground above.
The Sanctum - As the lava flowed down the valley it widened at this point and formed the largest chamber within the cave. The ceiling here is 15 feet high and the roof is about 20 feet thick. If you look carefully near the wall where the floor slopes upward, you will see two “Lava Tube Volcanoes.” These were formed by gases and hot lava bubbling up through the semi-molten floor of the cave.
Lavacicle Lane - When most of the molten lava drained out, the remaining lava still molten began to drip off the ceiling and formed drip pendants or “lavacicles.” They are sharp little points so watch your head if you are very tall.
Partial Collapse - Cooling of the solidified lava caused shrinking and cracking which weakened areas where the shell was thin and allowed them to collapse. The pile of boulders here is the result of such a collapse. Along the same wall, just ahead of the rubble pile, you can see traces of another collapse that occurred while the lava was still flowing. The jagged bits of rock in the wall were partially melted by the heat in the cave. This rubble pile was carried off by the still flowing lava.

Signs along return trail
Sanctum Roof - About 20 feet below you is the Sanctum, the largest room in Subway Cave. On the other side of the depression in front of you is the outside of Lucifer’s Cul-de-Sac. It is a short arm extending off the snake-like lava flow.
Trail’s End - You are about to climb on top of the lava tube for the last time along the trail. We hope you have enjoyed your exploration of Subway Cave. Lava tubes are just one of the wonders of nature in this fascinating geological world. We hope you have enjoyed Subway Cave and invite you to discover the many different natural wonders of Lassen National Forest.


About 24,000 years ago (USGS date of 24±6 ka) an eruption fluid basalt from a chain of spatter cones occurred about 2 miles south of here. Some of the vents can be visited along the Spatter Cone Trail. The spatter cones fed flow which extend nearly 18 miles north of the vents. The distal flows were fed be lava tubes such as the small segment accessible at Subway Cave. For more information visit the nearby Old Station Visitor Center.

Fee?: 0.00 (listed in local currency) Approximate Time to Finish: 1 hour Addtional Website URL: [Web Link] Brochure or Interpretive Signs: Interpretive Plaques/Signs Rate the Walk: Wherigo Cartridge: Not listed

Visit Instructions:
A picture at the start of the Trail or Walk is greatly appreciated. Additional photos taken during the course of the walk would also be of great benefit.

If there does not appear to be a defined beginning to the trail or walk, pick a logical place (e.g. close to parking) or where information about the walk or trail can be gathered.

Recent Visits/Logs:

Date Logged Log   09/14/2013 Volcanoguy visited it