The smoke was visible from downtown Lawrence, leading some to think calamity had struck the city's southern edge.
But it was merely men mimicking nature.
A crew led by Baker University biology professor Roger Boyd on Tuesday conducted a controlled burn at the Baker Wetlands.
"We try to burn about half of the wetlands every other year," Boyd said.
The burning, Boyd said, prevents trees, shrubs and sunflowers from overtaking the wetland's prairie grasses.
"Historically, there wouldn't be any trees here because the prairie would have burned, on average, two out of every five years," he said. "So burns like this are part of the natural process."
On Tuesday, burning was confined to the northern half of the 573-acre wetlands.
Though the leaping flames appeared menacing, Boyd said most of the area's wildlife was spared.
"Most of what's in there either runs out ahead of the flames or burrows down a couple inches," he said. "They get out OK."
Some motorists pulled over on Louisiana Street to watch the conflagration.
Not everything that was meant to burn did. Boyd said he may have to mow the large, resilient patch of sunflowers on the northwest corner of the wetlands.
"Not every place burns the way you think it would," he said. "There are patches out here that may have gone three years without a burn, and when that happens, you have to mow."
Boyd's crew wasn't the only one busy burning on the city's south side.
Fred DeVictor, director of the city's Parks and Recreation Department, said his crews started burning native grasses Tuesday on city land along Clinton Parkway. In coming days, they'll also do controlled burns at Naismith Valley Park, Prairie Park Nature Center and on 25 acres near Eagle Bend Golf Course.
"We do it to get rid of the weeds and the dead growth, to give new growth a chance to survive," DeVictor said.