During a recent hike on the Nāpau Trail in Hawaii Volcanoes National Park, one accompaniment was the throb of helicopter engines. The active flow from Pu’u O’o vent, and its ultimate outpouring into the ocean, is a great attraction for visitors and locals alike.

One way of seeing these events is on a helicopter tour and, as I sat at the Nāpau overlook, I noticed there was a clear order to those helicopter visits. A pair would arrive from the west, one a bit behind the other. One would circle the vent, the other visit the ocean entry. Then they’d switch. After 10 or 15 minutes, the two helicopters would head off to the northeast and soon after, the next pair would arrive.

For more information about Hawaii Volcanoes National Park, go to nps.gov/havo/.
 For more information about Kilauea Volcano and it’s eruptions, go to hvo.wr.usgs.gov/kilauea/history/main.html.