The lava flow above Pahoa started a fire Saturday afternoon, as it moved through light brush in a vacant lot.

At 2:45 p.m., the Hawaii County Fire Department and state Department of Forestry were working to contain the fire, which was not threatening structures.

The lava had not advanced since Saturday morning, when an overflight showed the flow front slowing and widening.

The flow front advanced about 50 yards and expanded to about 150 yards compared to Friday, when the flow was 100 yards wide and had moved about 180 yards from the previous day.

“The flow front has slowed considerably over the past day,” HVO reported on its website. “Along with this drop in advancement, webcam views show a reduction in smoke at the front over the past day.”

The flow is about 1.4 miles upslope from Apa’a Street on the outskirts of Pahoa and has advanced about 10.2 miles from its source at Pu’u ‘O’o crater. 

The active edge of the surface flow left the northwest corner of the Kaohe Homesteads and moved from the forested area to open land. 

“It is not yet clear if this reduction in advance rate is due to a drop in lava supply or simply the flow front filling a small local depression – in either case the advance rate could rise again in the coming days,” scientists said.

Depending on the speed of the flow, officials said, lava could reach Apaa Road in 13 days, to Pahoa Village Road (also known as Government Road) in Pahoa within 18 days, and Highway 130 in 21 days. 

Scientists with the Hawaiian Volcano Observatory said fluctuations in the flow advance rate are common for pahoehoe lava flows.