The south side of Mt St Helens tells a very different story
than the north side. Mt St Helens and
other Cascade range eruptions are generally
explosive due to the high amount of silica in the magma. But about 1900 years
ago, lava flowed from Mt St Helens like Hawaii’s
volcanoes. Some lava followed down a
stream channel and the top layer cooled and hardened. When the molten lava
underneath eventually drained, it left a long cave known as a lava tube. One of
these lava tubes is Ape
Cave on the south side of
Mt St Helens, which is about 2.5 miles long.
We’ve seen many caves, but this was our first lava
tube. We had two options: the upper
section (1.5 miles) with lots of rocks to negotiate or the easier lower section
(0.75 miles). Bill went through the upper
section and Barbara went through the lower section.
The lower section and some of the upper section of the cave
are just big tubes.
In parts of the upper section, rock from the ceiling fell
after the lava drained, leaving a higher ceiling and a jumble of rocks in the
tube.
Some sections were large, up to 88’ wide, and beyond the
ability of a small camera flash.
Water beads on the ceiling and walls, glistening in the
pictures, and intermittently falls in large drops. The temperature is 42
degrees in the cave even though the outside was over 80.
There are 2 “skylights” in the upper section where ceiling
collapse opens to the outside. One has the ladder for the exit.
The next stop on our trip is letterboxing on the southern Washington coast.
