Mt. St. Helen’s Ape Cave Lave Tube is the longest lava tube in the United States at about 2 miles long.
Lower Ape Cave is about .75 miles long and takes about an hour roundtrip. Lower Ape Cave is special because of the “meatball”. The “meatball” is a block of cooled lava that fell from the lava tube ceiling while lava was still flowing through the cave. This creates a dead end. Another feature of the Lower Ape Cave is the “railroad tracks” which is a shoulder or levee formed along the side of the lava flow. Flow
marks of the “railroad tracks” are seen on the walls and floors of the cave.
Upper Ape Cave is for more advanced adventurers. The tube is 1 ½ miles long and takes about 2 hours to complete. In the upper cave people must climb over about 27 boulder piles and scale an 8-foot high lava fall.
Sturdy shoes or boots are recommended along with warm clothing and three light sources.