Hawaii reports first serious injury from volcano as lava threatens escape routes

A stream of lava threatened to block a key Hawaii highway on Sunday that serves as an escape route for coastal residents, while the first known serious injury was reported from fresh explosive eruptions from the Kilauea volcano.

Man's leg shattered after being hit by lava splatter

Lava continues to flow on Hawaii's Big Island, bubbling as it travels toward the coast, destroying everything in its path 1:13

A stream of lava threatened to block a key Hawaii highway on Sunday that serves as an escape route for coastal residents, while the first known serious injury was reported from fresh explosive eruptions from the Kilauea volcano.

A homeowner on Noni Farms Road who was on a third-floor balcony had his leg shattered from his shin to his foot when hit by lava spatter, said Janet Snyder, a spokesperson for Hawaii County's mayor.

She added that lava spatters "can weigh as much as a refrigerator and even small pieces of spatter can kill." No other information was immediately available.

As lava destroyed four more homes, molten rock from two huge cracks merged into a single stream, threatening to block escape routes and touching off brush fires.

Bay and Amy Lou Henriques, evacuees from the Leilani Estates subdivision, come to an evacuee camp for dust masks in Pahoa, Hawaii, after the latest eruption of Kilauea volcano on May 17. (Ronit Fahl/AFP/Getty Images)

The erupting lava, which can reach a blistering 1,093 C, was expected to hit Highway 137 overnight if it kept up its rate and direction of flow, the County of Hawaii's Civil Defense Agency said.

Video shows active lava on ground and time lapse from Gemini Observatory on Mauna Kea 1:00

Authorities are trying to open up a road that was blocked by lava in 2014 to serve as an alternative escape route should Highway 137 or another exit route, Highway 130, be blocked, Jessica Ferracane of the National Park Service told reporters.

The park service is working to bulldoze almost a mile of hardened lava out of the way on nearby Highway 11, which has been impassable, she added.

Lava flows near a house on the outskirts of Pahoa during ongoing eruptions of the Kilauea volcano. (Terray Sylvester/Reuters)

The Hawaii National Guard has warned of mandatory evacuations if more roads become blocked.

But officials went house-to-house in the area to urge more residents to flee, Snyder said, though no head count of the new evacuation was available early Sunday.

They also warned of laze, clouds of hydrochloric acid and steam embedded with fine glass particles formed when hot lava hits ocean water.

For weeks, geologists have warned that hotter, fresher magma from Kilauea's summit would run underground and emerge some 40 kilometres east in the lower Puna district, where older, cooler lava has already destroyed 44 homes and other structures.

"Summit magma has arrived," U.S. Geological Survey scientist Wendy Stovall said on a conference call with reporters.

A woman takes a photo as an ash plume rises from the Kilauea volcano on Hawaii's Big Island on May 15. (Mario Tama/Getty Images)

"There is much more stuff coming out of the ground and it's going to produce flows that will move much farther away."

Fountains of bright orange lava were seen spouting at least six metres high, and spewing rivers of molten rock on Saturday.

Carolyn Pearcheta, operational geologist at the Hawaii Volcano Authority, told reporters that hotter and less viscous lava could be on the way, with fountains spurting as high as 180 metres, as seen in a 1955 eruption.

"We've seen the clearing out of the system," she said. "We call that the 'throat clearing' phase."

The area affected by lava and ash is small compared with the Big Island, which is about 10,360 square kilometres. The volcano has spared most of the island and the rest of the Hawaiian chain.

Officials have reminded tourists that flights, including on the Big Island, have not been affected. Even on the Big Island, most tourist activities are available and businesses are open.

New explosive eruption

At the volcano's summit, another large explosive eruption occurred around midnight, sending up a nearly three-kilometre-high ash plume, according to the Hawaiian Volcano Observatory. There was another explosion around 4 p.m. (10 p.m. ET), according to a Reuters reporter.

Scientists expect a series of eruptions from Kilauea, one of the world's most active volcanoes, that could spread ash and volcanic smog across the Big Island, the southernmost of the Hawaiian archipelago.

Kilauea sends plume of ash and debris nearly 9,000 metres up 0:49

That could pose a hazard to aircraft if it blows into their routes at around 9,100 metres.

Around 2,000 residents of Leilani Estates and Laipuna Gardens housing areas near Pahoa, about 48 kilometres south of Hilo, were ordered to evacuate due to at least 22 volcanic cracks that have opened.

Many thousands more residents have voluntarily left their homes due to life-threatening levels of toxic sulfur dioxide gas spewing from vents in the volcanic fissures. 

More than 300 people were staying at three different shelters as of Saturday, Snyder said. 

Steve Clapper stood in the rain outside a shelter where he and his mother have been staying since evacuating Leilani Estates. He sleeps in his truck with his dogs while his mother sleeps inside the shelter.

The uncertainty has made him want to get his 88-year-old mother, who has dementia and is on oxygen, off the island.

"We don't have any control over it, and this could go on for years," he said.

With files from The Associated Press