Waterspouts and Bench Collapses below Kilauea Volcano
by Jay Kelley
The waterspout occurred in 1998 during the winter months. At that time
there was about 600,000 cubic yards of lava a day, running into the ocean
below the Pu'u O'o vent. The steam plume resulting from the interaction
of sea water and molten lava roiled up in a dense white expanding column
like an actively forming cumulo nimbus cloud. Occasionally, small vortex
swirls of steam would form beneath the main plume almost like miniature
tornados. They would extend from the underside of the steam plume to the
surface of the ocean and would last for only a minute or two and then
dissipate as they moved down wind and the distance between the bottom
of the steam plume and the ocean surface increased.
One day when we were still above the top
of the pali 5 miles or so from the shoreline, we noticed what appeared
to be a water spout beneath the steam plume. The water spout was much
thicker than the usual steam vortices. At the base it appeared to be about
a hundred feet thick. We flew down to get a closer look and sure enough
it was definitely a water spout. It continued to gain energy and moved
further downwind gradually attaining a life of its own without the necessary
input of energy from the steam plume. The ceiling was about 4,000 feet
that day and the atmospheric conditions were unstable. The steam plume
had given birth to this water spout.
The water spout grew larger and became
self sustaining. Soon it had separated itself completely from the steam
plume and snaked from the ocean surface all the way up into the 4,000
foot ceiling. It moved south just off shore and continued for as long
as we stayed on the scene watching it. Several helicopters had flown past
it at about 500 feet. It was easy to see how big it was with the a helicopter
sillouetted against it. It would have been interesting to follow it to
see how long it endured, but our tour schedule precluded hanging around
to watch it.
From time to time there are bench collapses at the water front where
the molten lava builds out onto itself into the ocean. The terrain just
off shore is very steep and unstable. When enough lava builds out onto
this steep underwater terrain, it will slide and suddenly a substantial
hunk of acreage will disappear beneath the waves. These bench collapses
sometimes produce some interesting explosive activity at the shoreline
for a few days afterwards due to the entry of cold sea water into the
suddenly exposed lava tubes.
Occasionally the wave action into a sea
level lava tube opening will result in huge bubbles of lava being rapidly
blown up to 30 or 40 feet in diameter just on shore out of a vertical
hole in the top of the lava tube. These huge bubbles inflate in a second
or so. The thin film of lava hardens almost instantly into a glass like
substance, and the whole thing bursts into a zillion pieces like a huge
christmas tree ornament and goes twinkling and sparkling off in the wind.
Being a volcano tour pilot for the last
11 years during the winters here on the Big Island has afforded me the
opportunity to see some amazing sights. I feel fortunate to have been
privy to so much visually interesting phenomena. During the summer Alaska
is my home, and glaciers are a big part of flying there. Fire and ice
seem to dominate my flying at this stage of my career.
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