Lava creeping across roadways destroyed four homes and left dozens of others in the shadow of Hawaii’s Kilauea volcano isolated on Saturday, forcing more residents to plan for a possible evacuation.

Hawaii County Civil Defence said a fissure near the area of Lanipuna Gardens has been continuously erupting, releasing a slow-moving lava flow. If that lava threatens a nearby motorway, more people will be told to prepare for voluntary evacuation.

On Friday, fast-moving lava crossed a road and isolated about 40 homes in a rural subdivision, forcing at least four people to be evacuated by county and National Guard helicopters.

The wide lava flow was “very active” on Saturday morning and advancing at rates of up to 300 yards per hour, scientists from the Hawaiian Volcano Observatory said.

Hawaii Volcano
As lava activity erupts in the background, cars drive down Hwy 132 in Hawaii (AP Photo/Marco Garcia)

Police, firefighters and National Guard troops were securing the area of the Big Island and stopping people from entering, Hawaii County Civil Defence reported.

The homes were isolated in the area east of Lanipuna Gardens and Leilani Estates. Both areas had 40 structures, including 26 homes, decimated by lava over the past two weeks.

Three people still in that area on Friday night were initially advised to shelter in place and await rescue by helicopter first thing on Saturday. Since then, two of them got out on their own in the morning and one was evacuated by air, said Janet Snyder, spokeswoman for Hawaii County.

“They shouldn’t be in that area. We told them they will be locked in,” said county managing director Wil Okabe. “It’s more serious now. They’re putting their lives at risk.” He said he hopes people heed evacuation warnings.

County officials have been encouraging residents in other parts of the district to prepare for potential evacuations.

Lava crosses the road at Pohoiki Road near Pahoa, Hawaii (Marco Garcia/AP)
Lava crosses the road at Pohoiki Road near Pahoa, Hawaii (Marco Garcia/AP)

Experts are uncertain about when the volcano will calm down.

The Big Island volcano released a small explosion at its summit just before midnight on Saturday, sending an ash cloud 10,000ft into the sky. The US Geological Survey’s Hawaiian Volcano Observatory said eruptions that create even minor amounts of ashfall could occur at any time.

This follows the more explosive eruption on Thursday, which emitted ash and rocks thousands of feet into the sky. No-one was injured and there were no reports of damaged property.

Scientists said the eruption was the most powerful in recent days, though it probably lasted only a few minutes.

It came two weeks after the volcano began sending lava flows into aread 25 miles to the east of the summit. A new lava vent — the 22nd such fissure — was reported Friday by county civil defence officials.