Hawaii Volcanoes National Park, United States – An eruption at Kilauea began at 9:17 a.m. on March 10 and produced record lava fountains from the south vent that rose as high as 1770 feet.

The eruptive activity continued for nine hours and generated large amounts of tephra that fell across visitor overlooks and nearby communities.

Most of the fallout accumulated at the Uekahuna overlook and the Kilauea Military Camp within the park, as well as parts of Highway 11 and the Volcano Golf Course community. Sections of Highway 11 and Hawaii Volcanoes National Park were temporarily closed so crews could carry out tephra cleanup.

Lighter tephra was also reported in other parts of the Volcano Golf Course community, along with Volcano Village and Mauna Loa Estates. These areas received smaller amounts of fallout, including lapilli sized particles larger than 1/16 inch or 2 millimeters. Communities farther away reported only ash smaller than 1/6 inch or 2 millimeters and Pele’s hair, according to the U.S. Geological Survey.

More than 200 tephra fall reports were submitted through the “Is Tephra Falling?” webtool. The first report arrived around 10:30 a.m. from areas inside the park and nearby communities surrounding the Kilauea summit.

Tephra fall raises concerns for residents who depend on rooftop rainwater catchment systems. Fluoride can coat tephra particles and dissolve into stored water. Testing of catchment tanks after a previous eruption episode showed fluoride levels between 0.06 and 0.3 parts per million, well below the U.S. Environmental Protection Agency limit of 4.0 parts per million for public water systems.

Runoff collected from roofs during the first rainfall after the tephra fall showed higher levels. Roofs that had not been cleared recorded fluoride levels between 7 and 10 parts per million, while runoff from a cleaned roof measured about 1.5 parts per million, showing that removing tephra can significantly reduce contamination.

Other potential contaminants linked to volcanic ash, including arsenic, cadmium, chromium, copper, and lead, were too low to detect. In most cases, water affected by ash is expected to taste unpleasant or appear discolored before contaminants reach levels of health concern.

Kilauea has been erupting intermittently within the summit caldera since December 23, 2024. Inflation in the summit region suggests another eruptive episode could begin between March 28 and April 14.

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