Four people were evacuated by helicopter Friday evening after a fast-moving lava flow cut across Pohoiki Road and isolated about 40 homes.
Hawaii County Civil Defense said the crossing occurred near Malama Ki Place, and the flow, fed by fissure 20 near Lanipuna Gardens, was about 3 kilometers — or 1.86 miles — from Highway 137.
The residents were evacuated by the Fire Department and Hawaii National Guard. Though road access was severed to the homes, at least three vehicles were seen escaping by going off-road, said Talmadge Magno, Civil Defense administrator.
Another vehicle with about three passengers was stranded on the other side of the flow.
Magno said it became too dark to rescue them by helicopter but it was possible for them to walk to safety. He said helicopters will return Saturday morning and crews remained on the ground overnight monitoring the flows.
It was not clear if any more residents remained. Civil Defense was advising people still in that area to stay in a safe place and wait for further instructions.
Magno said the vent appeared to have waned and the flow wasn’t immediately threatening the highway. No mandatory evacuations were being issued Friday evening, though he reiterated residents who depend on that road should prepare to leave if they haven’t already.
“People in that area need to be making their decisions now,” he said.
The U.S. Geological Survey said the flow was advancing 300 to 400 yards an hour as of 6:30 p.m. Friday.
Aaron Mitchell, who lives in Lanipuna Gardens but has since evacuated, said he was driving on Pohoiki Road to check on his home when the lava crossed the road. He estimated lava was moving 10 feet per minute.
“It was swallowing trees like every minute,” Mitchell said. “It was probably the most terrifying moment of my life.”
The crossing occurred during a day of increased volcanic activity in lower Puna and the introduction of pahoehoe lava flows at three fissures. Most flows have been dominated by ‘a‘a lava.
Jim Kauahikaua, a geophysicist with Hawaiian Volcano Observatory, said most of the activity Friday was on the northeast portion of the eruption area, between Pohoiki Road and Highway 132.
Magno said Friday afternoon that a home in Lanipuna Gardens became the 40th structure to be destroyed since the eruption started more than two weeks ago.
Mitchell said he was trying to be “the eternal optimist” but expected his home was gone.
The eruption along Kilauea’s East Rift Zone began May 3 and now totals 22 or more fissures from Leilani Estates to near Highway 132. About 2,000 people have been displaced, mainly from the Leilani and Lanipuna subdivisions.
HVO geologists say lava samples show there is a mix of old and new magma that’s reaching the surface.
The older magma, which has dominated the eruption for the first two weeks, is likely left over from a 1955 eruption.
The newer magma, which is coming from the area of the Pu‘u ‘O‘o vent or Kilauea’s summit, will be hotter and more fluid, allowing it to travel faster. That appears to fit with what was seen on Friday, though geologists say additional sampling will give them a more clear picture.
“All signs are we are now seeing magma coming down from the summit entering into the system,” said Wendy Stovall, HVO geologist, while discussing a sample from fissure 21 in Leilani.
“We think this lava will continue to erupt at the surface, probably in a more voluminous fashion.”
Kauahikaua said large cracks in Leilani continue to grow as the magma dike gets closer to the surface. The cracks, a yard or more wide, are located 100 to 200 yards away from the fissures, he said.
Kauahikaua said that’s also an indication that new magma is being introduced to the eruption.
Geologists say additional steam-driven eruptions are likely at Kilauea’s summit following three substantial ash emissions this week, two of which are considered steam explosions.
The recent explosions have increased the size of Overlook crater, which hosted the lava lake inside Halema‘uma‘u crater, from 12 to 34 acres. A small depression about 15 acres in size on the east side of Halema‘uma‘u also has formed.
The magma column under the crater has receded in response to the lower Puna eruption.
Email Tom Callis at tcallis@hawaiitribune-herald.com.