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Ape Cave Lava Tube

Photo: Greg Willis / CC BY-SA 2.0 · source

🕳️ Caves

Ape Cave Lava Tube

Cougar, WA · Mount St. Helens

About

Roughly 2,000 years ago a river of basalt poured off the south flank of Mount St. Helens, crusted over, and drained out the bottom, leaving behind the longest continuous lava tube in the continental United States. You descend a steel staircase into a cool, dark passage that runs about 2.5 miles, headlamp catching ripples frozen into the walls and lavacicles hanging from the ceiling where molten rock once dripped. The lower route is an easy walk to the Meatball, a boulder wedged overhead in the tube, while the upper route asks you to scramble over rubble and haul yourself up an eight-foot lava wall, and the cave holds a steady 42 degrees no matter the season.

Highlights

Longest continuous lava tube in the continental US (about 2.5 miles)Formed by a Mount St. Helens lava flow roughly 2,000 years agoThe Meatball, a boulder lodged overhead in the tubeLavacicles and ripple walls along the lower passageEight-foot lava wall scramble on the upper routeA constant 42 degrees year-round, bring a headlamp

Getting there

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Curated guides that feature Ape Cave Lava Tube.

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America's Best Caves

Step out of the daylight into another world: the longest cave on the planet in Kentucky, a desert chamber big enough to swallow a stadium in New Mexico, an underground waterfall in Tennessee, and a living crystal cavern in Arizona. Some you walk, some you ride a boat through, and one you crawl with a headlamp. America's great caves and caverns, from the national parks to the lantern-lit show caves.