Ape Cave

Ape Cave lava tube is one of the longest cave tube in the main 48 state body of the United States, and one of the longest in the world. Located south of, and near Mount St. Helens in Gifford Pinchot National Forest about 2,000 years ago, fluid basaltic lava poured down the southern flank of the volcano. As the lava flowed, chunks of the lava’s surface cooled, crashed and fused together creating a hardened crust. In turn, the crust insulated the molten lava beneath, allowing it to remain fluid and travel down to the Lewis River Valley. During this eruptive period, hot fluid lava pulsed through the tube for months, possibly up to a year, until the eruption subsided. As a result of this rare eruption, a spectacular 13,042 foot (3976m) long lava tube, the third longest in North America, was created!

Why is it called "Ape Cave"?
Ape Cave was discovered in 1947 by a logger named Lawrence Johnson when his truck fell into a sinkhole which opened into the cave. However, the cave was not explored until the early 1950’s when a scout troop, led by Harry Reese, lowered a team of scouts down a 17-foot overhang to the cave floor. Named by the Scout Troop in honor of their sponsor, the St. Helens Apes. This local group was made up primarily of foresters. The sponsor’s name, St. Helens Apes, may have come from an old term used for foresters in the area, “brush apes,” or from the legend of Bigfoot.

Only in the summer, a naturalist leads Ape Cave tours through the lower part of the cave. Or season you are on your own, but pick up a brochure available at the cave entrance to find out more about the cave and caving equipment you will need to explore on your own.

Two routes of exploration are available in the cave and an above ground trail Ape Cave #239, connects the main and upper entrances. The lower cave (the one I took and easiest) is a 3/4 mile hike that takes 1 hour round trip. The sandy floor found in the lower section of the cave formed when volcanic ash, pumice and other debris washed into the cave following eruptive episodes as recent as 450 years ago. Debris from these events filled the cave’s lower section, ultimately plugging its lower end. As a result, visitors must return to the main entrance in order to exit the cave. The challenging upper cave is 1.5 miles long and requires climbing over piles of rocks. That upper cave route takes 2.5 to 3 hours.

What should you bring?
The temperature remains near 42ºF/6ºC year round. It can also be windy and wet in the lava tube. I highly recommend warm clothing and boots. And most important of all, a bright flash light and backup batteries or a clean burning lantern.