Ape Caves

At 12,810 feet, it's one of the longest continuing lava tubes in the world. The 1,900-year-old cave on the southern slopes of Mount St. Helens was first explored in 1951 by an informal youth group called the St. Helens Apes. Members named themselves Apes after the Sasquatch who supposedly stalked the area, and the label stuck to the cave as well. Those modern-day Merlins felt the magic the first time they peered into the darkness and followed the eerie tube. Years later, the ''what's next'' feeling remains in the cave's cold, drafty, pitch-black world.

With well over 100,000 visitors a year, Ape Cave is one of the most popular spots in the Gifford Pinchot National Forest after the volcano visitor centers and Windy Ridge.

Visitors enter a gaping hole in the landscape and start down a steep staircase. Once on the cave floor, they can go south, down the smoother portion of the cave to a dead-end about three-quarters of a mile away. Or they can head north, up a slight incline and over a rocky, hazardous route that runs more than a mile to the upper entrance.

Cavers who choose the tougher north route can climb out there and hike back on an above-ground trail.

North or south, the cave offers startling evidence that Mother Nature is a potter. Its textures and shapes first came to life when molten lava gouged the surface of the Earth, following a stream bed.

Over the duration of the eruption, the lava pushed into the ground, and as it flowed, it cooled. In the beginning, the torrent of lava formed a trough, but a crust formed across the top surface, forming a roof on the tube.

Inside, much of the lava drained away, leaving a tunnel with a rocky shell as thin as a couple of feet in some places.

As the lava flowed inside the tube, it melted the walls, creating ripples and sags like cooling chocolate. In some places, rock surfaces are coated with a glistening dark glaze like that on modern pottery or porcelain.

Unlike other geologic formations, the Ape Cave formed over a period of days. But the innards have changed through hundreds of years.

Three different volcanic eruptions, for instance, created mudflows that entered the tube and are visible in neat layers in some places.

The most recent are 320 years old, an eyeblink in geologic time. The other two are older, but researchers don't know just how old.

Volcanic sand washed into the lower entrance, making the south path a safer and more comfortable hike. But several features close-in on the rocky north arm should not be missed.

One is the 3-foot-deep fluted gutters that line the walls. They were formed by narrower lava streams that followed the initial massive surge. The lava would rise and congeal, then recede, leaving the ledges.

The other awesome sight is the Big Room.

It should be seen with plenty of lanterns throwing shadows across its 70-foot-wide, 30-foot-high expanse. The boulders crowding half of its space may be loose, so climbers should be careful.

Forest Service workers and cavers from a group called the Oregon Grotto of the National Speleological Society help clean the cave of litter, beer bottles and graffiti. Partying, pets, smoking and food are forbidden in the cave.

Cave litter not only is ugly, it harms the forms of life that depend on the cave environment.

Pets are endangered by cave drops and sharp rocks. Their refuse damages the cave experience for others. Visitors who cannot follow these rules are asked to leave.

The Ape Cave has a parking area, trail, interpretive displays and restrooms. But you should still bring your own drinking water. The trail is barrier-free up to the entrance of the cave.

At the Apes Headquarters, visitors can rent lanterns and buy books and maps in summer.

Interpretive tours in the cave will be held several times a day from Memorial Day to Labor Day. They will talk about the formation of the cave and about cave biology, ecology and history. For specific times of tours, call monument headquarters, (360) 247-3900.

After the tour, visitors can continue exploring on their own.

Apecaves Lodging Information

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