Upper and Lower Ape Cave
Upper and Lower Ape Cave
The longest known lava tube cave in North America, Ape Cave offers a challenging scramble with a surface return trail along its upper portion, while Lower Ape Cave is an easier out-and-back underground hike. Although other caves were known in the area as early as the 1890s, Ape Cave was not discovered until the mid-twentieth century. Probably in November or December 1951—the exact date has been lost to time—a logger by the name of Lawrence Johnson found the main entrance to Ape Cave. Johnson descended a short distance into it by climbing down a handy tree trunk. He then tossed rocks into the darkness and realized that he had found a much larger cave than could be seen from the surface. Johnson contacted the Reese family, who owned and operated a store a few miles west of the town of Cougar and were avid cavers. A few days later Leonard Reese was the first person to be lowered to the floor of Ape Cave. Ape Cave was formed approximately 1,950 years ago by a lava flow that originated from Mount St. Helens. This flow’s unique form of lava called cave basalt constructed the 12,810 feet of passages that make up the cave. Cave basalt is a form of pahoehoe (a Hawaiian word pronounced pah-hoeyhoey)— a low-silica-content lava. In the case of Ape Cave, this very fluid pahoehoe lava flow was deepened as it flowed down a preexisting streambed; the flow rate increased, and thus it stayed hotter than the surrounding lava flow. The lava along the sides of the streambed as well as a crust over the top cooled enough to solidify, encasing the lava stream inside. Then the remaining liquid lava flowed on out of the tube, leaving the longest lava tube cave known in North America. At some time, possibly about 1480, a sandy lahar flowed into the cave’s main entrance. This lahar filled portions of Lower Ape Cave, blocking it about 4,000 feet below (south of ) the main entrance and leaving the sand and bits of light-colored pumice we see today.
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Directions to: Upper and Lower Ape Caveprint directions
Trail Statistics & Information
|Elevation Gain||900 ft|
|Skill Level||Upper cave: very strenuous; lower cave: moderate|
|Season||May through October|
|Trailhead Elevation||2,120 ft|
|Top Elevation||2,450 ft|
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