Kilauea Eruption: Terrifying Videos, Images Show Lava Flow Intensifying

Lava flow from Kilauea volcano on Hawaii's Big Island intensified Monday, a day after relative calmness in the region. On Monday, the Hawaiian Volcano Observatory said two new fissure segments had broken the surface.

One of these segments were on a forested area southwest of Leilani Estates and another near pre-existing fissures, officials said as thousands of residents were evacuated from their homes in the Leilani Estates and Lanipuna Gardens neighborhoods. A dozen lava vents had opened in streets of the Puna district and 35 structures had burned down as of Monday.

"There's no sign of this slowing down," Hawaii's Civil Defense Administrator Talmadge Magno said Sunday. "We had some pauses yesterday, but there seems to be a lot of magma underground."

According to Jackie Young of Hawaii Public Radio, some lava fountains were spewing molten rock 230 feet high, causing massive concerns in the areas about further destruction caused by Kilauea, which erupted Thursday.

"Authorities emphasized that the eruption remains dangerous and constantly changing," Young reported. "Warnings were also reiterated about the toxic levels of sulfur dioxide gas. Some first responders have already become sickened from exposure."

Several terrifying videos and photos emerged on social media showing red-hot lava flowing on the streets, engulfing homes, trees and cars. A timelapse video posted online shows one stream of lava crawling across a street, toward a parked car, which later erupted in flames before being consumed by the lava.

A photo made available by the U.S. Geological Survey (USGS) shows the entire north portion of the Overlook crater in the Mount Kilauea volcano.

Magno told ABC News that the Civil Defense Agency was starting to prepare for the worst as a new fissure opened Sunday night in the Leilani Estates area.

"It ramps up our response more... Even though you're thinking about the worst-case scenario, it's starting to come to fruition, so you go, 'OK, we need to get ready for that worst-case scenario,'" Magno told ABC News.

On Saturday, Magno said that "the eight vents were pretty active, to the point where lava was spewing and the flow started spreading so we got additional damage out there. I'm not sure what the count is, but we thought it was just continue to go. Fortunately, seismicity has kinda laid down and the vents have gone quiet now."

The island also witnessed a 6.9-magnitude earthquake Friday, which resulted in landslides near the coast. The USGS said Sunday the island had experienced more than 500 earthquakes.

"This is lava, that is definitely destroying people's homes — we don't have an exact count — but it is a devastating situation and it's going to be everyday that it goes on," Hawaii County Managing Director Wil Okabe said Saturday. "Mother nature, there's no way we could've predicted this."