The ultimate destination of many of the Kilauea's lava flows is the ocean. When water comes into contact with the 2000-degree lava, it immediately turns into steam, expanding into billowing clouds that whirl away with the wind. This "instant boil" has many unpredictable, dramatic, and dangerous effects.

One effect of the mixture of lava and water is the production of black sand. As the water boils, it fragments the lava into small pieces, which get further beaten by subsequent waves. At the base of nearly every active ocean entry is a black sand beach, which is usually short-lived, carried away by the passing ocean currents soon after the activity stops. If the activity continues, lava continually oozes over the sand, building the beach higher and higher until the new lava is no longer in contact with the water. This fresh lava then cools and hardens, building up a bench of solid ground on top of the sand. As more and more land builds up, the bench gets heavier and heavier. Meanwhile, the constant wave action chips away at the sand underneath the solid rock bench. You can guess what happens next - at some point the bench might become so unstable with its own weight that it just collapses into the ocean. A short period of huge explosions usually ensues, a new beach begins to form, etc.

Sometimes the bench activity isn't quite so extreme. In the spring of 1996 while I was volunteering, there had been a fairly quiet period of several weeks with lava flowing through a tube and calmly into the ocean. One day the bench simply subsided a few yards. The end of the tube through which lava was flowing suddenly dropped below the surface of the ocean. Water pressure forced seawater into the end of the tube, where the 2000-degree lava boiled it almost instantaneously. With nowhere for the steam to escape, it exploded through the top of the submerged tube into the air, with awesome results!

As reports of explosive activity started to come in, we drove down to the end of Chain of Craters road with our binoculars. In the distance we could see huge orange bubbles of lava exploding high into the air - intense! I wondered how long it would continue, hoping for an opportunity to get closer to the action! Sure enough, the next day a group of us hiked out the ~3 miles to the ocean entry. The wind wasn't in our favor, and we couldn't see too much from our direction of approach. But we could sure hear and feel it! Loud popping, booming, and splashing sounds, shaking the ground. From the other side of the ocean entry, we had a better view - showers of red lava fragments bursting through the steam in all directions! We still couldn't see the base of the explosions, but it was an awesome sight none-the-less! I kept hoping for the steam to clear, and when it finally did we were treated to the amazing sight of a peristant pool of lava that was churning and sloshing, and every few minutes a huge bubble would press up 20 feet into the air and explode!

A couple days later another group of us ventured out again, and this time we had perfect viewing conditions - the activity had moved a bit further inland, away from the steam cloud, and the weather was darkly overcast, creating a dramatic grey backdrop to the bright orange lava. The activity continued for several days before settling down into the usual benign steady state, and during that time I think I hiked out 5 times. Each time was a bit different, and it was amazing to see how the landscape changed by the minute...