PAHOA, HAWAII (REUTERS) - A stream of lava threatened to block a key Hawaii highway on Saturday (May 19) 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 sitting on a third-floor balcony got hit with lava spatter," said Ms Janet Snyder, a spokesman for the Office of the Mayor, County of Hawaii.
"It hit him on the shin and shattered everything there down on his leg," she said, adding 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 magma destroyed four more homes, molten rock from two huge cracks merged into a single stream, threatening to block escape routes. It was expected to hit Highway 137 overnight if it kept up its rate and direction of flow, the County of Hawaii's Civil Defence Agency said.
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, Ms 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.
The Hawaii National Guard has warned of mandatory evacuations if more roads become blocked.
For weeks, geologists have warned that hotter, fresher magma from Kilauea's summit would run underground and emerge some 25 miles east in the lower Puna district, where older, cooler lava has already destroyed 44 homes and other structures.
"Summit magma has arrived," US Geological Survey scientist Wendy Stovall said on a conference call with reporters.
"There is much more stuff coming out of the ground and its going to produce flows that will move much further away."
Fountains of bright orange lava were seen spouting at least 20-feet high, and spewing rivers of molten rock on Saturday.
Ms Carolyn Pearcheta, operational geologist at the Hawaii Volcano Authority, told reporters that hotter and more viscous lava could be on the way, with fountains spurting as high as 600 feet, as seen in a 1955 eruption.
"We've seen the clearing out of the system," she said. "We call that the 'throat clearing' phase."
At the volcano's summit, another large explosive eruption occurred around midnight, sending up a nearly 10,000 feet high ash plume, according to the Hawaiian Volcano Observatory. There was another explosion, 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.
That could pose a hazard to aircraft if it blows into their routes at around 30,000 feet.
There had been no reported injuries or deaths since the eruptions began on May 3.
Around 2,000 residents of Leilani Estates and Laipuna Gardens housing areas near Pahoa, about 30 miles 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 sulphur dioxide gas spewing from vents in the volcanic fissures.