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

A stream of lava threatened to block a key Hawaii highway on Saturday 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 Janet Snyder, a spokesperson 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 Defense Agency said.

Helicopters were rushed in to rescue four trapped residents after lava flowing from Hawaii's Kilauea volcano isolated a cluster of homes, local officials said late Friday, one day after the volcano erupted and shot a huge plume of ash miles (kilometers) into the sky.

Hawaii County Mayor Harry Kim wrote on Twitter that "fast-moving lava from Fissure 20 has crossed Pohoiki Rd near Malama Ki Place," near the Puna forest reserve.

The lava is "isolating appx 40 homes in area," he wrote, adding that four people were "safely evacuated" by Hawaii County and National Guard helicopters.

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.

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.