More than a dozen possible tornadoes were reported Saturday as forecasters warned residents across the nation's midsection to brace for "life-threatening" weather.
An apparent tornado took down barns, outbuildings and large trees in southeast Nebraska, and Johnson County emergency director Clint Strayhorn said he was still trying to determine how long the twister was on the ground and how much damage it did.
"I'm on a 2-mile stretch that this thing is on the ground and I haven't even gotten to the end of it yet," he said as he walked the path of destruction near the Johnson-Nemaha county line. He described a line of downed trees and a barn that was destroyed. He didn't immediately know of any injuries.
"I'm trying to make sure everyone's OK," Strayhorn said.
In northeast Nebraska, Boone County Sheriff David Spiegel said baseball-sized hail damaged vehicles, shattered windows and tore siding from houses in and around Petersburg, about 140 miles northwest of Omaha.
Two possible tornadoes were reported farther south in Nebraska near the Kansas border and as many as 10 others were reported in largely rural parts of western and central Kansas, including one north of Dodge City that was said to be on the ground for a half-hour, weather officials said. An old schoolhouse and outbuildings were damaged in Hodgeman County in western Kansas and a home was damaged near Lorretta in Rush County in central Kansas.
In Salina, tornado sirens sounded after a possible tornado was spotted near the central Kansas community. National Weather Service meteorologist Mike Scott said tornadoes also were reported near Sawyer in Pratt County, near Seward in Stafford County, near Timken and Rush Center in Rush County and near Hanston in Hodgeman County.
Sharon Watson, spokeswoman for Kansas Division of Emergency Management, said officials will continue to monitor the storm into early today.
"The challenge on this particular storm is the severity level that is being forecast across so much of the state. It is one that is causing us much concern and requiring a lot of attention to determine exactly what is happening," she said.
The most dangerous weather was expected to come later, and National Weather Service officials issued a stern warning for residents to prepare for overnight storms that could spawn fast-moving tornadoes. Officials said a large area could be at risk for dangerous storms.
"The threat isn't over with tonight, unfortunately. Severe weather is possible again tomorrow from east Texas and Arkansas and up into the Great Lakes," said Bill Bunting, chief of operations at the Storm Prediction Center, which is part of the National Weather Service.
Tornado sirens sounded across Oklahoma City before dawn Saturday, and at least three possible tornadoes were reported west and north of the city in the central part of the state, Oklahoma Department of Emergency Management official Michelann Ooten said.
One of the suspected tornadoes in central Oklahoma hit near the small town of Piedmont, taking a similar path as a tornado last May that killed several people, Mayor Valerie Thomerson said.
"Because of last year, we've had a lot of new people put storm centers into place," the mayor said, adding that no major damage had been reported in the town northwest of Oklahoma City. "We're all very anxious about this afternoon."
The Storm Prediction Center gave the sobering warning that the outbreak could be a "high-end, life-threatening event."
It was just the second time in U.S. history that the Storm Prediction Center issued a high-risk warning more than 24 hours in advance. The first was in April 2006, when nearly 100 tornadoes tore across the southeastern United States, killing a dozen people and damaging more than 1,000 homes in Tennessee.
The threat prompted University of Nebraska-Lincoln athletic officials to cancel the annual spring football game minutes before Saturday's kick-off.