Saturday, March 30, 2024

Hike: Trail of Two Forests & Ape Cave Lower Passage, Cougar, WA

Getting There

It's 28 miles from Woodland to the Cougar. There are a couple of gas stations here. Continue east on SR-503 which becomes Rd 90 for 9.5 miles to Ape Cave. Looks for the sign to Ape Caves, June Lake, Climber's Bivouac, Ape Canyon & Lava Canyon which is Rd 83. It's 0.3 miles to Trail of Two Forests and 0.7 miles to Ape Cave.

This was our second field trip with the 2024 Volcano Naturalist Program with Mt St Helens Institute. We had a carpool signup since there was going to limited parking in the Trail of Two Forests parking lot. I added my car to the list and a fellow volunteer signed up. It was nice to have someone to talk with on the drive up and back.

I didn't expect anyone to signup, so I had booked a motel in Woodland for Saturday night. I still wanted to have the company so I took my rider back to their house in Portland after the field trip and drove back to Woodland for my stay.

The Hike

Distance: 3.57 miles
Elevation Gain: 358 feet
Maximum Elevation: 2,110 feet

We met the rest of group at the Trail of Two Forests parking lot. Ape Cave is closed right now until May 18th but we had special permission from the USFS to explore the cave.

After introductions and a preview of what we were going to see and do, we took a walk around the TTF boardwalk, stopping at a few spots along the way. I got some more details that I will be adding to my talks with visitors.

Since I am a volunteer, I was selected to carry a radio and assist with the field trip.

There was no need for snow shoes since the road to the cave was mostly clear of snow. When we reached Ape's Headquarters, another volunteer and I was asked to talk a little about our experiences volunteering at the cave.

We had lunch in the sun and got ready for the adventure.

It was great to have a guide explore the cave with. She had a bunch of details that I didn't know from my own research or from my mentor. I will be adding it to my own storytelling when I volunteer at the cave later this year.

Some highlights:

  • The ledges inside the cave that look like bathtub rings are Cave Levies. The lava flow slowed down and there was cooling & hardening of the lava.
  • Air currents are mostly due to temperature differences between the surface air and cave air. Cold air flows down to lowest points. If air on surface is warmer than the cave air, cold air moves downhill. If air in the cave is warm than the surface air, cold air moves uphill.
  • The holes on the side of the cave are from blowouts. Moisture in the surrounding soil/earth was heated and turned to steam and exploded the rock into the cave. You can see how thick the cave wall is because the rock from the riverbed is brownish.
  • Rock fall inside the cave happened when the cave was cooling. Geologists have checked the debris after recent earthquakes and have not discovered any new rocks. Seems to be stable.
  • The railroad tracks were formed when the volume of lava was diminishing and slowing down, allowing it to cool and harden.
  • Ripples on the walls are rock that was remelted and began sagging due to gravity.
  • 450 years ago, a lahar flowed down over the cave entrance and mud & rock flowed through the cave and was deposited on the floor.
  • The white stuff on the walls is cave slime, a combination of fungus + bacteria that work together in symbiosis.

It was great to take our time and discuss what we found. Several folks were able to find small insects on the cave wall.

At one point, we all turned off our lights and just listened to the sounds and experience the cave in total darkness. The instructor light a single wooden match. We became "Cave Apes", pledging to protect with amazing, natural place.

At the end of the lower passage was a pile of something, fabric, basically trash. We were picking up trash along the way. Even though the cave is "closed to the public", there's not gate to prevent people from going in.

There were several folks in there with us. The instructor just told them they the cave was closed and there are lots of signs saying as much but we weren't there to enforce anything.

Two classmates from Seattle were interested to visit the viewpoint above the cave parking lot. I'd mentioned it in my talk. I couldn't find a good map due to poor cell service but someone else was able to pull up a map. I was glad to have sparked some interest.

Looking for resident insects on the walls

the Meatball