The lava emerged from a vent in June. It started moving through thick vegetation that made it difficult at times to see deviations in topography, he said.
But it's looking like the lava is headed to Pahoa Village Road, which runs through downtown.
“Laterally it might be a little to the right or left, but it will head to the road”—unless it suddenly stops moving, Vanderkluysen said.
What's less predictable is where a new branch will sprout from the miles (kilometers)-long flow and spread in other directions.
“We don't have a good grasp of where breakouts are going to happen,” he said.
HOW HOT IS THE LAVA?
About 2,100 degrees Fahrenheit (1,148 Celsius), according to Janet Babb, spokeswoman for the Hawaiian Volcano Observatory. “Ten times hotter than boiling water.”
But the temperature starts to drop after the lava is exposed to air.
“The crust cools down, and you can walk on it after a few days,” Vanderkluysen said.