(CNN) Two of the three main lava channels from the volcanic eruption on Hawaii's Big Island have merged to create only two entry points into the Pacific Ocean, according to USGS scientist Jim Kauahikaua.
Fissure 22 split into two flow lines on Thursday, but came back together later in the day.
Fissure 7 is producing the largest amount of lava, according to USGS volcanologist Wendy Stovall.
Small eruptions are continuing at the summit of Kilauea. An explosion reported Thursday produced an ash plume that rose up to 10,000 feet and "carried slightly more ash" than other recent ones, the USGS said.
Authorities are urging people to stay away from the areas where lava is entering the Pacific.
When hot lava hits the ocean, it can form a nasty product called laze -- a mashup of lava and haze -- and send hydrochloric acid and volcanic glass particles into the air.
Laze can cause lung, eye and skin irritation. And it has proven deadly in the past.
"This hot, corrosive gas mixture caused two deaths immediately adjacent to the coastal entry point in 2000, when seawater washed across recent and active lava flows," the Hawaiian Volcano Observatory said.
People around the world have been transfixed by images of red and orange lava fountains oozing out of volcanic vents on Hawaii's Big Island. Now a new color has joined the mix: the blue flames of burning methane gas.
A photo shared by the US Geological Survey shows striking blue flames peeking through the cracks in a street. Lava from the Kilauea volcano has been burning through plants and shrubs, producing methane.
The gas "can seep into subsurface voids and explode when heated" or "emerge from cracks in the ground several feet away," the USGS said. Once ignited, it produces a blue flame.
"It's very dramatic. It's very eerie," USGS scientist Jim Kauahikaua said.
It has been more than three weeks since the Kilauea volcano's massive eruption, sending a smoldering flow of lava into residential areas and forcing thousands of residents from their homes, and the danger has not passed.
Residents in the Leilani Estates community have seen their neighborhood transformed by the lava. Streets turned into rivers of black molten rock, the vegetation has rotted and now they are fearful their homes could be swallowed by the cracks.
Tam Hunt took photos Monday of his neighbor's house, showing ominous cracks splitting the ground under the home. While the family home is still above ground, a corner of the property looks like it's on the verge of crumbling into the abyss below.
"I saw the family checking their house on Friday and the crack was not as bad. I went back Monday and noticed that it had gotten worse, so I texted (the homeowner) about it," Hunt said.
Hunt said the property has been in the neighbor's family since 1991 and the couple moved into the home right before they had their two children, but now it seems they'll never be able to call this place home again.
"I expect the home to be completely gone soon. Every time we go back to see the damage, we notice that the earthquakes keep making the cracks wider and wider," said Hunt.