HILO >> The Puna Geothermal Venture power plant on Hawaii island was facing a new threat as lava from two fissures entered the property Saturday.

Hawaii County Civil Defense officials reported that lava from two fissures that began in the Leilani Estates subdivision — fissures 7 and 8 — ran onto the property shortly after midday Saturday, across Pohoiki Road.

Civil Defense administrator Talmadge Magno did not say Puna Geothermal Venture facilities were in imminent danger of being consumed, but he did say the flow was moving in the direction of Highway 132 that also borders the company’s property and would present new challenges for access and escape routes for people living in areas served by the highway, including Kapoho and places closer to the coast in Lower Puna.

“We’re watching that,” he said. “Everybody’s preparing their plans for if 132 is blocked by lava.”

The power plant was shut down shortly after the Kilauea eruption began May 3. Wells have been plugged and flammable gas called pentane removed to reduce the chance of explosions.

Magno said the lava flow was probably close to a mile from the highway. If there is enough volume, he said lava could progress toward the highway given how steeply the land descends in the area.

Tina Neal, scientist in charge for the U.S. Geological Survey, said one estimate was that this flow was moving 30 yards per hour Saturday.

In another development, four explosions from the Kilauea summit overnight between Friday and Saturday sent ash plumes 12,000 feet or higher above sea level. As of Saturday night, Halemaumau crater was producing small bursts of volcanic ash that was slowly being pushed downwind, southwest into the Kau District.

Meteorologists are warning that wind patterns could change Monday or Tuesday, delivering bad air to populated areas.

Winds are expected to continue blowing south-southwest into today, said John Bravender of the National Weather Service. But more volcanic eruptions — coupled with changing wind patterns to the north-northwest starting Monday — “will bear watching,” Bravender told reporters Saturday.

“From a vog and SO 2 (sulfur dioxide) standpoint, this could lead to higher concentrations of gases in more populated places, Pahoa and other places across the Big Island,” he said.

Hot gas coming out of cracks along Highway 130 — the major road leading into Lower Puna — show that levels of hydrogen sulfide are “below the detection limit,” said Wendy Stovall of the USGS.

The levels indicate the heat coming out of the cracks “is just steam.”

“Yes, it is hot,” Stovall said. “There is magma beneath those cracks, but it is not close to the surface and it has not breached the water table as far as we know.”

Evidence of hydrogen sulfide, Stovall said, “means that magma is encountering the groundwater and it’s starting to boil away the groundwater, which would mean the magma is moving closer to the surface. … But there’s no indication that cracks around Highway 130 are close to showing signs that magma is at, or close to, the surface.”

Lava has been pouring out of about two dozen vents in or near Leilani Estates for more than three weeks, covering 2,372 acres, or 3.7 square miles. Two flows feeding into the ocean near MacKenzie State Recreation Area are ongoing.

On Saturday, Hawaii County was able to make its first determination of how many homes — as opposed to structures that can include homes, sheds, barns and other buildings — have been destroyed. The county said 41 of the 82 structures consumed by lava were homes.

Also Saturday, Civil Defense distributed free masks for ash protection at Cooper Center, Hawaiian Ocean View Community Center, Pahala Gym Annex and Naalehu Nutrition Center. Civil Defense said the masks do not protect against gasses and vapors and provide only filtering for ash.

Kilauea Lower East Rift Zone Fissures and Flows, May 26 by Honolulu Star-Advertiser on Scribd