History of Ape Cave

Formation of the Cave

Ape Cave was formed during a massive lava flow sometime around the year 80 CE. The cave is comprised of one main channel and a few side channels, unlike the intertwining, mazelike lava tubes of Lava Bed National Monument in California. The main flow of the cave followed an existing stream bed, widening and deepening the channel as it forged its way ahead. 

As the top crust of the lava flow cooled and hardened, feeder channels of still molten rock formed. The channel which produced Ape Cave kept carving its way deeper and deeper into the stream bed, while the top crust of the channel continued to thicken. In some places, the roof of the cave is up to 60 feet thick. As the lava gradually ceased to flow, the molten rock was replaced by incredibly hot volcanic gasses that glazed and melted the rock walls of the cave. The blue-black glazing on miniature stalactites is apparent in many places throughout the upper cave.

About 450 years ago, a mudflow entered the main entrance of the cave, leaving behind the wide, flat sandy floor of the lower cave. 

Discovery of the Cave

The actual date of the discovery of the cave is not known. Estimates range from 1946 to 1951. Sometime in those years, a logger from Amboy, Washington was the first man to find the cave. Lawrence Johnson was in the area of the main entrance when he noticed a tree growing at an odd angle. When he investigated, he found a large sinkhole that opened into a dark tunnel. Johnson walked into the tunnel, tossing pebbles ahead of him until he found himself at the edge of an overhang; ahead was a large, pitch black, echoing cavern. When his day's work was finished, Johnson returned to the cave with the rest of his logging crew, as well as all the lights and tackle they had with them. They reached the edge of the lip, but no one was willing to lower himself into the darkness.

Johnson contacted Harry Reese, a local community leader and an avid caver: a few days later, Reese and his sons (members of a local Boy Scout Troup who called themselves the Mt. St. Helens Apes) were the first to explore Ape cave. These young men extensively explored the cave throughout 1952. Interestingly enough, they found no evidence of previous human exploration.

Mapping of the Cave

The Mt. St. Helens Apes originally mapped the cave. Later, in early 1978, the Cascade Grotto of the National Speleological Society made a detailed map of the cave to determine its total length. The cave is now divided into two sections- the Lower Cave, downslope from the sinkhole entrance, is about 4,000 feet long. The Upper Cave extends nearly 7,000 feet upslope from the main entrance. 

The Cave Today

Ape Cave is now extensively mapped, easily accessible, and enjoyable for all ages. The lower cave is an easy walk, with wide, sandy floors and large passages. The upper cave is more difficult- its floors were not affected by the mudflows and are still rough. Many passages in the upper cave are filled with broken rock- chunks of basalt that have cracked and fallen from the walls and ceiling of the cave. 

On the surface above the cave is an interpretive center showing the features, formation, and creatures of Ape Cave. During the tourist season, the bathrooms and a small bookshop are open to the public. Lanterns and flashlights can be rented from the bookshop, and a guided interpretive tour of the lower cave is also available.