Hawaii volcano eruption: Incredible pictures show Kilauea lava fissures UP CLOSE


However, Hawaiian volcanoes produce "curtains of fire" as lava fountains erupt along a portion of a fissure.

Almost 20 volcanic fissures have opened and are spewing lava and poisonous gas across the big island Tuesday morning. A major concern for emergency services is lava devastating roads that could lead locals away from danger.

Hawaii National Guard spokesman Jeff Hickman said if either highway is hit by lava, mass evacuations would be triggered.

Overall, almost 2,000 people have been told to evacuate since May 3 and lava has destroyed more than two dozen homes.

A river of lava more than a mile long is flowing toward the ocean from one of the fissures.

Two more fissures opened in the last 24 hours, bringing the total to 19.

"It's optimistic to think that this is the last fissure we're going to see", Hawaiian Volcano Observatory scientist Steve Brantley said.

On Monday, the Hawaii State Department of Health warned residents in Lanipuna Gardens of unsafe levels of sulfur dioxide gas.

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The gas is especially harmful for elderly, young children and babies and people with respiratory problems, and may cause choking, the agency officials said Monday.

The lava lake in the crater has been dropping since May 2, which increases the chances for a phreatic explosion.

Officials added the residents should leave the area of volcanic activity, avoid outdoor activities, drink plenty of fluids, avoid smoking, close windows and recirculate the air conditions when smog levels are elevated. But water may not be entering the crater, as feared, and gas and steam may be safely venting, scientists said.

Lava on Sunday spread across hundreds of meters of private land and loud explosions rocked the neighborhood not far from the Leilani Estates subdivision, where more than a dozen other active vents opened over the past week.

Smoke and lava erupt from a fissure near a home on the outskirts of Pahoa during ongoing eruptions of the Kilauea Volcano in Hawaii, U.S., May 14, 2018.

The industry grew the fastest on Big Island a year ago compared with other islands in the archipelago, pulling in about US$2.5 billion in visitor spending. Board executive director Ross Birch says this is the "first leak we're seeing out of the bucket".

Most of the Hawaii Volcanoes National Park remains closed to visitors due to ongoing seismic activity and the possibility of an explosion at the summit.