By Rob Samuelsen
Around the time of human origins, pressure from a large stratovolcano pushed forth gas and lava into a fast-moving river of molten rock. As this viaduct of fiery sludge moved forth, an outer crust hardened forming a protective tube as a means of conveyance. Backpressure from noxious gas catapulted the remaining rock out, leaving behind a unique hollow lava tube cave in the San Francisco volcanic field just west of Flagstaff. While it was formed 700,000 years ago, it was discovered by lumbermen in 1915 and has been a popular destination for dirt road adventurers ever since.
Easily accessible when Coconino National Forest roads are dry, this mile-long lava tube is a fun adventure for most everyone. Its entrance is a scramble down through a section of collapsed ceiling and is definitely the most challenging part of the easy hike. The basaltic lava rock insulates which often leaves ice in the entry way of the 42-degree tunnel, even in mid-summer. Between the slippery ice and the abrasive rock, skinned knuckles and knees are not uncommon. Once through the entrance, the cave passage is a level, cylindrical, and symmetrical underground hallway, not unlike the New York City subway system. It proceeds a mile underground until it pinches out at the end. Then you exit by the same way you entered. The floor of the cave has some unique folds and crevasses that make each step an ankle twisting adventure and there are some cracks and hoodoos that create hiding places for those with a wicked sense of humor. Overall though, the dark igneous creates a foreboding presence into the pitch-black abyss buried deep in the bowels of Mt. Humphries.
Fortunately, the Lava River Cave is a singular path with only one “jug handle” detour making it virtually impossible to get lost! Nevertheless, like any cave, the deep darkness can be disorienting, so three sources of light (flashlights, glowsticks, candles, etc.), sturdy shoes, gloves, jackets, and a helmet are highly recommended. Even those who are well prepared, inevitably, someone always needs a Band-Aid!
Because the Lava River Cave is in the Coconino National Forest, there is open primitive camping all around the cave. Each time I’ve been there, I’ve camped nearby because it’s a beautiful ponderosa pine forest in the cool alpine climate of the Flagstaff area. (Note: You are prohibited from camping within a mile of the cave because of congestion – maybe 15 cars!) This is a high adventure activity the entire family can enjoy.
