An ash plume from the Kilauea volcano’s summit crater on Hawaii’s Big Island has risen as high as 12,000ft above sea level, according to monitors.

Ash has been wafting continuously from a vent in the crater, Halemaumau, and drifting south west, causing ash fall and volcanic air pollution as far as 18 miles away, the Hawaiian Volcano Observatory said.

Authorities have issued an ash fall advisory for the island’s southernmost district, and a “red” warning for pilots and air traffic controllers as the ash could disrupt flights.

Ormat Technologies, which owns a geothermal energy plant in the area, said there is a low risk of lava impacting the facility.

The plant, Puna Geothermal Venture, which provides about a quarter of daily energy demand on the Big Island, was shut down after Kilauea first erupted on May 3.

A new fissure opens up near PahoA new fissure opens up near Paho (US Geological Survey/AP)

Elsewhere, authorities reported a new fissure opened in the Lanipuna Gardens area, bringing the number of cracks in the ground spitting out lava and toxic gas to nearly 20 since the eruption began.

Another fissure that opened up last weekend is sending molten rock crawling towards the ocean at about 20 yards per hour.