Gifford Pinchot National Forest

Cavers, Expect the Unexpected!

Take:

• Three sources of light – Clean-burning lanterns (propane or white gas) or flashlights with strong batteries and bright bulbs.
• Sturdy shoes/boots – The lava tube floor is uneven and covered with jagged rocks.
• Warm clothing – The temperature remains near 42ºF/6ºC year round. It can also be windy and wet in the lava tube.
• A friend – Also, let someone else know where you are going and for how long.

Which Way Do I Go?

Lower Cave - Easier Route

The main entrance divides the cave into two sections, the upper cave and lower cave. The three-quarter-mile (1200m) lower portion takes about one hour round-trip to complete. Interesting geological features include the meatball and the railroad tracks.

The meatball is a block of cooled lava which fell from the lava tube ceiling while lava was still flowing through the cave. It floated on the surface of the lava flow and was ferried downstream until it became wedged in a narrow spot 12 feet (4m) above the present cave floor.

The railroad tracks are levees that formed along the side of a tongue of flowing lava. As the fluid lava drained out of the tube, the levees remained intact.

The sandy floor found in the lower section of the cave formed when volcanic ash, pumice and other debris washed into the cave following eruptive episodes as recent as 450 years ago. Debris from these events filled the cave’s lower section, ultimately plugging its lower end. As a result, visitors must return to the main entrance in order to exit the cave.

Upper Cave - More Difficult Route

The 1½-mile (2100m), upper portion of the cave takes about 2½ hours to complete, returning on a surface trail. Cavers must climb over approximately 27 boulder piles and scale an 8-foot (2.5m) high lava fall.

The boulder piles, called breakdown, formed after the eruption subsided and the fluid lava drained from the tube. As the lava tube cooled, it began to shrink and crack. These cracks weakened the ceiling and walls causing parts of them to collapse. The entrances to Ape Cave formed in this way.

There is a skylight in the tube near the upper exit. However, to finish the upper cave, continue on through the tube to a permanently attached metal ladder. Serious injuries have occurred when individuals have attempted to exit the cave through this skylight.