A lava flow that began last month on Kilauea volcano is advancing at a rate of about 220 yards per day and, at its current flow rate, could reach the Pulama Pali in about 10 days as it passes a section of the abandoned Royal Gardens subdivision and, possibly, make its way to the ocean.

The flow, from the east slope of the Puu Oo vent, was about 2.7 miles long Thursday and is not threatening populated areas.

The flow appears to have captured most or all of the lava output from Puu Oo.

Another lava flow on the northeast slope of Puu Oo that also began May 24, and a lava flow that began June 27, are no longer active.

The active flow is moving southeast over old lava fields along or just outside the Hawaii Volcanoes National Park boundary.

It’s developing a tube system as it advances.

“Skylights,” or holes in the hardened lava above the tubes, provide glimpses into the flowing lava below, as seen in photos released Thursday by the Hawaiian Volcano Observatory.

“If and when it (the lava flow) reaches the coastal plain and then the ocean depends on the evolution of a tube system and constancy of lava supplied from the vent — variables that are difficult to forecast at this time,” forecasters said.

The Pulama Pali is a steep slope above a coastal plain built up by previous lava flows. If it reaches the pali and plain, the lava might become visible from Kalapana.

The last time lava entered the ocean was in 2013.

Scientists have given the lava flow an informal nickname — “61g,” based on the record system scientists use to keep track of the eruption. The breakout is episode 61g in the long-running eruption of the volcano.

The June 27 flow, at more than 13 miles long, was the longest since Kilauea started erupting again in 1983. The flow made its way to within yards from Highway 130 after reaching the Pahoa area in 2015 — crossing a street, oozing into a Buddhist cemetery, destroying multiple structures, burning a house and penetrating the fence line of the Pahoa Recycling and Transfer Station. The Hawaii National Guard was sent to help for about three months, and President Barack Obama declared the lava flow a major disaster.