Admittedly, calling it part of a volcano is somewhat misleading. Some 2,000 years ago lava streamed down St. Helens. The outer edges of the stream cooled and formed a hardened crust; the inside flowed for months. What was eventually left behind was the longest lava tube in the continental U.S., which sat undiscovered until a logger stumbled upon the tunnel in 1947.
Also, there aren’t any apes. Instead, the cave gets its moniker from the first youth group to fully explore the cave in the early 1950s, the St. Helens Apes.
These days, rock falls and settling have divided the tube into two very distinct and very chilly sections. The three-quarter-mile-long lower cave is the most popular because it’s shorter, and because the terrain is relatively flat with few obstructions, and easy to make your way through in about 45 minutes.
I, however, prefer the upper tunnel because it’s more challenging. The one-and-a-half-mile segment is darker—so dark that without a lantern you literally cannot see an inch in front of your face—and has more rock falls to negotiate, including one that requires a climb over an eight-foot-high lava fall. The two-and-a-half-hour walk in the tunnel’s constant 42 to 47 degree temperature meant an interesting, fun workout without a lot of sweat.