Ape Cave near Mount St. Helens

I have driven past the turnoff for Ape Cave many times when hiking near or on Mount St. Helens but have never stopped to explore it. Caves aren’t something I’m excited about. I enjoy seeing pictures of them and find them fascinating but the thought of actually going underground into a big hole – sometimes narrow and tiny - gives me big anxiety. HOWEVER, when I’m around my brother... I somehow become braver. I might even have SUPERPOWERS! haha

Together we ventured into Ape Cave today...

I was surprised I was as comfortable as I was and really proud of us for doing it. I kept my breathing controlled (as well as my thoughts… until Russ mentioned “earthquakes” – such a funny guy, huh?) and I didn't feel the rapid heartbeats of anxiety until he said he wanted to show me just how dark it was by having us turn off our lights (we each had TWO). Yikes. It was completely black. Silent too. I didn’t dare take a step in any direction. With our lights ON, it was really fascinating and I truly enjoyed looking around. There were water drips and puddles throughout making it a little humid although it was pretty cold in there. There were fallen boulders from the ceiling (another scary thought) and cracks in the ground. I later read there were cave mice and other little creatures in there but thankfully didn’t see any of those… just a creepy face up on the wall.

We only saw a few other people while inside - one couple anxiously trying to get back to the entrance - the man’s voice full of anxiety as he was telling us about their hike further into the cave. Russ and I turned back when climbing up and over boulders became part of the required experience. We didn’t want to risk a fall or twist an ankle with our climb up St. Helens on the schedule for tomorrow. Exploring the Cave was great and very interesting but I sure felt relieved when we finally saw daylight, smelled the fresh air, and were on TOP of the earth again instead of within it. 😅

I found a blog post on the web when searching out the Ape Cave… much more information than I could tell you about it! You can find the entire blog post here (giving credit to the writer) but the main part is below:

The 'main' entrance is actually a sink hole that has been fitted with stairs, allowing easy access to the main cave 40 feet below. The cave itself is approx. 12,800 feet in length. It was formed about 1900 years ago when a lava flow from Mt. St. Helens filled an old river canyon with lava. As the exterior of this new lava bed cooled, the interior continued to flow, eventually forming a long, hollow tube. The information booth had a sign that said it took roughly 85 days for this to occur. Over the years, erosion has covered the upper layer of the tube making it virtually indistinguishable from the surrounding forest. The Ape Cave is currently the longest known lava tube in the Northern Hemisphere (or continental US depending on what literature you read!).

There are three 'entrances' to the cave, two of which have been modified for easy access. The 'main' entrance enters the cave about a third of the way along its length. We went along the shorter (or lower) length first. This part of the cave was about 3/4 of a mile long and was very easy to traverse. The ground, although hard and somewhat irregular, was fairly level and posed no large obstacles. The cave ceiling varied in height from roughly 5 to 30 feet (much more than 15 feet on the average). We passed through several large 'rooms' where you could see where the lava had etched long, straight lines into the cave edges and dripping lava had cooled to forms 'frozen' drops on the ceiling. The vertical drop in the lower section was only about 150 feet.

The lower section ends gradually, beginning with a 5 foot high tunnel that eventually peters off to nothing. The literature that we picked up describing the cave indicated that back in the Early Kalama Period, about 450 years ago, an eruption caused a large amount of ash to be washed into the lower section of the cave, giving it its smooth floor. Seasonal rains still cause the terminus of the lower cave to change on an annual basis.

After reaching the end of the lower section, we backtracked up to the main entrance where we entered the longer, upper section. This part of the cave was MUCH more difficult to traverse (and a lot more fun too)! There were many rock piles (where the roof had collapsed years ago?) that had to be traversed. These ranged between 5 and 25 feet in height. The ceiling height again varied from 5 to 30 feet but averaged less than in the lower cave. There were several sections where we had to climb up very steep grades (45 to 70 degrees) ranging in height from 3 to 25 feet. Midway through this section is a 90 degree, 10 foot vertical rise that you have to traverse using just foot and hand holds.

2019 Hike 37/52

3 miles