Calling all spelunkers! The lower Ape Cave at Mt. St. Helens is a 1.5-mile out-and-back walk through a fascinating geologic formation. This is a moderately easy hike for adults and older kids. There is almost no elevation gain, but the floor is uneven and slippery in places, making it more difficult to traverse than a regular trail. If you bring toddlers, be prepared to lift and carry them at times. Because of the tripping hazard, I wouldn’t recommend bringing babies in backpack or front packs, but we saw plenty of people who did just that. Use your own judgement when bringing very young children.
The Ape Cave, located near Mt. St. Helens in Cougar, Washington is not a cave, but is actually a 13,042-foot lava tube–the third longest lava tube in the United States. This unusual formation was created when lava flowed down the south side of Mt St Helens 1,900 years ago. The name has nothing to do with apes, much to my son’s disappointment, but is named after a group of explorers who found the cave, called the Mt St Helens Apes.
There are two hikes within the Ape Caves, the lower and upper caves. The lower cave is much easier and suitable for families. The upper cave requires physical agility as you will need to climb over large boulders and even scale an 8-foot lava wall- not recommended for young children. This post only covers the lower cave.
Getting there: From I-5, take exit 21 and follow SR 503 to Cougar. Once you drive through Cougar, follow the signs to Ape Cave. We drove in from Kelso and used google maps.
What to bring:
5 dollars cash to purchase a parking pass if you don’t have a Northwest Forest Pass. There is no place to get change, you put the money in an envelope and tear off a ticket to place on your car windshield. You can also purchase an e-pass from home before you go, print out and bring along on your trip.
Plenty of light. Two light sources per person are recommended. Headlamps are great for keeping your hands free, but make sure you have good quality ones that can rotate and point downward and have very strong light. I had a headlamp that wasn’t strong enough that I just put in my pocket because it didn’t help me at all. Same goes with flashlights. Dollar store lights or iPhone flashlights will not emit enough light. I found a strong flashlight worked best because I could point it at the ground which was very uneven. Several groups in the cave had the rental propane lanterns (available for rent at the Ape Cave Headquarters near the entrance for $5) which worked really well.
A backpack. You’ll want your hands free.
What not to bring:
No pets! Animals are not allowed in the caves because of the delicate ecosystem. We saw folks that had to leave their dogs locked in the car because they brought a pet. No smoking, food or drink (except water) allowed inside. No open flames, flares, fireworks or firearms. Littering inside the cave carries a $200 fine and you cannot take any rocks away with you. Also, don’t touch the walls. The “cave slime” that grows there takes years to regrow.
What to wear:
I recommend long pants, preferably jeans, because there are some areas in which you will climb over rocks. Bring a sweater or sweatshirt as well. The temperature stays a constant 40 degrees, and with the uneven floor, you can never really walk fast enough to break a sweat. I also recommend a hat, not necessarily for warmth, but because water drips from the ceiling.
Some reports advised bringing gloves. I didn’t feel the need for gloves, but one of the teens I brought said her hands got really cold.
Wear sturdy shoes! The floor is very uneven and wet in places. Athletic shoes with a good tread are just fine. If you have hiking boots, you could wear them, but in my opinion boots are not necessary for the Lower Cave. We saw people trying to walk in flip-flops, and it wasn’t pretty!
Parking and fees: There is a parking lot at the Ape Headquarters Center for which you will need a Northwest Forest Pass. You insert $5 cash in an envelope and put the ticket on your windshield. At this lot, there are bathrooms (vault toilets- really stinky!) and souvenirs/lantern rental at the Ape Headquarter Center.
During the winter months, this area gets snowed in and you will need to park about a mile away at the Trail of Two Forests lot, get a Sno-Park Permit, then hike in.
From the parking lot a short, paved walkway will take you to the cave entrance. Be sure to check out the station staffed by a ranger with lots of info on the caves and bats. Before you enter, stop at the shoe brush station and clean your shoes. This helps cut down on the transmission of the fungi which causes White Nose Syndrome– a disease that harms bats. You will also need to use the shoe brushes after exiting the cave.
Enter the cave via a stairway. Once you get to the bottom, if you continue straight ahead, this takes you to the easier, lower cave. There is a sign with arrows pointing to the upper and lower cave areas but it is tucked under the staircase and we didn’t see it until we were heading back.
The cave is huge and I never felt claustrophobic at all. I found I had to keep the flashlight pointed at the floor while walking because it is extremely uneven. But my adventurous kiddos had no problem and were way ahead of me the whole time. We stopped every few minutes to just look around at the walls and ceiling. It never got boring because the inside of the tube looks different every few feet.
In addition to the uneven floor, there are a couple of areas in which you will need to climb down or over large rocks. They weren’t huge, but they could present a problem for really little kids. That being said, we saw plenty of parents lifting toddlers over rocks.
Two interesting features are the “railroad tracks” near the entrance, where a smaller tube within the tube formed, leaving a ledge on either side. Also of note is the “meatball” which is a ball of lava that floated through the tube until it got stuck. When you see the meatball, you are almost to the end.
The tube eventually narrows then dead ends. At the end, there is a tunnel that a small person can army- crawl into. There is nothing on the other side, so you have to back out. Your kids will probably want to go in the tunnel (like mine did) but I don’t recommend it!
This is the end of the lower cave. From here you just turn around and walk back. We really enjoyed the walk back because we were more familiar with the terrain and could really enjoy the scenery.
My whole family really enjoyed this trek, my 13-year-old even called it the highlight of her summer! We didn’t see any bats, much to my kids disappointment. We went on a Sunday and it was very crowded. It would probably be more peaceful on a weekday. The little store offers a free brochure called Exploring the Ape Caves which I recommend picking up before you go in, it has a helpful map.