An enormous ash cloud towered above Kilauea’s summit Tuesday and dusted downwind communities, but the expulsion was short of the “big one” that could eject boulders inside Hawaii Volcanoes National Park.
Such an explosive event remains in the cards, geologists say, assuming groundwater seeps into the receding magma column beneath Halema‘uma‘u Crater and debris falling from crater walls plug the vent, allowing pressure to build.
“It’s probably going to wax and wane for the foreseeable future,” said Michelle Coombs, the lead scientist at the Alaska Volcano Observatory, while discussing the ash emissions. She is assisting colleagues at the Hawaiian Volcano Observatory with media briefings.
“It’s a very dynamic system, both down at the rift zone and at the summit,” Coombs said.
The plume, the largest of several recent emissions, could have been caused by rockfalls hitting the receding column of molten rock, water intrusion or a combination of both, she said.
The column, which until recently supported a lava lake at the surface, is dropping at the summit in response to the East Rift Zone eruption in lower Puna that started May 3, displacing about 2,000 people and destroying 37 structures so far. That could allow groundwater to enter the volcanic shaft, which can cause a more explosive eruption at the summit.
According to geologists, the ash plume rose to 10,000-12,000 feet above sea level and spread ash as far as Pahala, 18 miles to the southwest. An aircraft warning was issued near the volcano.
Amery Silva of Pahala said small amounts of ash were collecting on cars, but was otherwise hard to notice.
“That’s been happening for the past two weeks,” she said.
Steve Brantley, HVO deputy scientist-in-charge, said geologists are studying the ash to see if there is evidence of water intrusion inside the magma column.
“We’re recording overall deflationary tilt as the magma column presumably continues to withdraw,” he said.
The ash is not toxic but can irritate the throat or lungs.
David Damby, a volcanologist with the U.S. Geological Survey, said the ash dispersion was light Tuesday, but residents should remain indoors if it becomes more substantial.
“As it falls, if it touches you, it’s not as an immediate concern,” he said, while comparing it to volcanic gases. “You just want to limit your exposure to it.”
Damby said water catchment tanks should be covered.
An N95 mask can provide short-term protection from particulates, such as ash, but not gas, according to Alvin Bronstein, chief of emergency medical services with the state Department of Health.
Damby said officials are discussing how to distribute those masks to affected areas.
Because of the risk of a larger explosion, the national park remains closed, and crowds gathered along roads around Volcano to watch the billowing cloud.
Volcano resident Margaret Kaufman said she could taste the ash earlier but was not worried unless the winds changed.
“This is my second volcano,” she said. “I did Mount St. Helens in 1980 and that was very scary. This one’s very polite though.”
That’s a different story down on the rift zone, where fissures continue to pop up between Pohoiki Road and Highway 132, also known as Pahoa-Kapoho Road.
Coombs said two new fissures — Nos. 20 and 21 — emerged near Lanipuna Gardens, but were producing only a pad of lava.
Fissure No. 6, located near Leilani Avenue and Pohoiki Road, became active again and was producing lava fountains and spatter as of 4:45 p.m.
Fissure No. 17, which has produced the longest flow yet, was waning, but its flow, about 1.5 miles long, was still inching forward.
Officials have been worried the flow could make its way to Highway 137 along the coast. Coombs said it was about 1.25 miles away, but less of a concern than the day before.
“It’s trending in the right direction right now,” Coombs said. “We’re not as worried as when it was moving 150 yards an hour. It’s moving 20 yards an hour to the best of our knowledge.”
On Tuesday, officials opened Highway 130, which has been closed because of ground cracks, to local traffic only after placing plates in the affected area.
Wil Okabe, county managing director, said Government Beach Road, which connects with Highway 137 at “Four Corners” near Kapoho, will be paved as early as today along a 4-mile stretch. That road might become an evacuation route if other routes are severed.
The eruption started in Leilani Estates, but new fissures have been concentrated near Lanipuna, located off Pohoiki Road on the southeast side of Puna Geothermal Venture.
Both subdivisions have been evacuated, though a few residents in Leilani have stayed.
Lanipuna resident Kieba Blacklidge said she’s been on the mainland during the eruption and has watched everything from afar. She said a friend grabbed some of her personal belongings, but she’s not sure if she will have a home to go back to.
“This is worse than a horror movie,” Blacklidge said. “It’s so surreal. Is it really, really happening?”
Civil Defense officials continue to try to kill two geothermal wells at PGV to prevent an unabated gas release, but it wasn’t clear when that work will be complete. The power plant is shut down because of the eruption.
Shelters remain open at the Pahoa and Keaau community centers.
A Salvation Army distribution center is available from 9 a.m.-noon and 2-5 p.m. until Saturday at the Pahoa shelter. After Saturday, it will be open during the same hours Tuesday, Thursday and Saturday.
Displaced people can request supplies, including water, canned food and hygiene products.
All supplies come from donations, with the Food Basket being the largest contributor. The Food Basket recommends cash donations.
Supplies also are being taken to the Keaau shelter.
The Hawaii Fire Department reports that air quality is still condition red, meaning severe conditions might exist, around fissures in the southeast area of Lanipuna and surrounding farm lots on Pohoiki Road.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
Email Tom Callis at tcallis@hawaiitribune-herald.com.