The images from Hawaii are striking.
Lava is spreading fast and ripping through homes and habitats. It's a dangerous situation but a fascinating one for scientists.
Geoscience professor John Luczaj is keeping a close eye on the lava from the campus of UW-Green Bay.
"There's a relatively stationary hotspot underneath this part of the state right now," Luczaj said.
Luczaj studied the lava flow in Hawaii back in 1993.
"It's kind of a neat personal connection for me," he said.
If he went back today, Luczaj would see a Hawaii that's vastly different.
"I also think back to where I was and I put myself geographically in the same spot and the places where I visited that were just rainforests are now being covered by lava," he said.
It's a similar situation for Tim Flood, a professor of geology at St. Norbert College.
"We actually drove through the neighborhood now that's been blocked off," Flood said.
Flood visited the volcano area earlier this year. There were no signs of what was to come.
"No indication at all, and that's not atypical for volcanoes," he said.
Professors said the volcano has actually been continually erupting since 1983, but the speed and the danger is now moving faster. The lava moving is changing the Hawaii that the professors last saw.