Back in Portland I headed up to the slopes of Mt St Helens with some folks to explore the ape caves – lava tubes which formed some 1900 years ago during a rare lava spewing eruption. They say that lava pulsed through the tubes for several weeks before draining to leave the empty shells behind. The caves weren’t discovered until the 1950’s. If the basalt walls of the tube hadn’t succumbed to the freezing and thawing and broken down to form a hole in the roof the tubes might never have been found.
There are many wonderful features in the caves. The walls are wonderfully sculpted in curvy forms to mark the meandering flow of the lava over the valley floor. It has a semi vaulted ceiling which open now and then to large chambers, some of which have a second tier or ledge – almost as if two lava tubes merged together. The odd wrinkly surfaces of the ceiling and some of the draping formations may be the result of remelt – flowing lava half filling the tube heated gas enough to melt the basalt rock above, which then sagged and draped beautifully. We didn’t see any bats on that wrinkled surface, but maybe spotted some guano.
Click through below and follow our captioned journey through the Ape Cave Lava Tubes. We journeyed the 1 1/4 miles of the upper passage – underground for some hours in the darkness with our torches, lamps, and rented propane lanterns.
PS: apologies for the hiatus as my camera got fixed