(BIVN) – “My biggest worry”, said USGS Hawaiian Volcano Observatory geologist Carolyn Parcheta, “is people being trapped.”

Parcheta was speaking to media at a press conference in Volcano on Saturday, the day after a fast moving lava flow on the lower East Rift Zone crossed Pohoiki Road near Malama Ki Place, isolating approximately 40 homes in the area.

The first emergency message from civil defense about the flow came at 5 p.m., after the flow had already cut through Pohoiki. Four people were evacuated by helicopter that evening.

“It is a very dynamic situation. The Fissure 20 flow that started yesterday, at the start of my watch, we were not expecting to start,” Parcheta said.

The fissure was building a little perched lava channel and feeding stuff mostly east, Parcheta said, and then “the south levee broke.” That’s when it flooded around the east side of Lanipuna Gardens.

“To me, that is a very scary scenario, and that’s what concerns me most, is that people might be trapped by something like that,” Parcheta told media.

“When it first broke out yesterday,” Parcheta continued, “we had a rough estimate about 400 meters per hour…. That’s hard to get around, quickly, if you don’t know it’s coming.”

“Our goal is to identify when changes are happening that might produce these kind of flows and warn civil defense to help people get out of the way,” Parcheta said.