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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