Western Kansas survey crews took advantage of calm conditions Wednesday to assess damage from severe weather that swept through the Great Plains, and the National Weather Service said more storms could be on the horizon.

Weather service meteorologist Andrew White in Dodge City said multiple tornadoes struck Ford and Hodgeman counties during a two-hour span Tuesday night, including an EF-2 twister that caused damage in western Ford County. Preliminary reports indicate that at least one of the tornadoes was a half-mile wide.

The tornadoes, which injured at least two people, were part of a series of storms that also pounded the Plains with rain and hail. One person drowned in central Oklahoma after a vehicle was swept off a road, and a 13-year-old boy was found safe in northeastern Arkansas three hours after falling into a flooded drainage pipe.

White said the forecast shows an enhanced risk of strong storms on Thursday, but nothing like the ones that broke out Tuesday. Forecasters say unstable air could allow tornadoes and large hail to form in southern Nebraska and northern Kansas in the late afternoon and early evening on Thursday.

Along with damaging homes, Tuesday's storms prompted officials to temporarily close U.S. 50 because a tractor-trailer was toppled, White said. He said a large propane tank tipped over and leaked near Dodge City, where 3-inch hail also was reported.

Emergency management officials in Ford County reported that two people were critically injured by tornadoes, the Kansas Adjutant General's Department said in a statement early Wednesday. Megan Walsh, a spokeswoman for Western Plains Medical Center in Dodge City, said two tornado victims who were brought into the emergency room were treated and released. The Adjutant General's Department did not return calls seeking to confirm whether those victims were the ones mentioned in its statement.

The drowning in Oklahoma happened early Wednesday when a vehicle was swept into a drainage culvert near the small town of Davenport, about 50 miles northeast of Oklahoma City, the Highway Patrol said. The National Weather Service said 3 to 6 inches of rain fell in parts of Oklahoma.

In Arkansas, the boy who fell into a storm drain wasn't seriously hurt. Police Cpl. Jason Chester told television station KAIT that the boy said he clung to a pole. He was rescued after two officers heard his cries for help.

Elsewhere, several structures were damaged when a "probable" tornado touched down in northeast Oklahoma, near Bristow, according to the weather service. The Oklahoma Highway Patrol said no one was injured.

In Michigan's Upper Peninsula, two weak tornadoes snapped pine trees, the National Weather Service said. No injuries were reported.

Several tornadoes were reported in Colorado, but the most serious damage appears to have been caused by hail. The weather service reported hail caused extensive damage to buildings and vehicles near Platner and Otis in Washington County. Tornadoes knocked down power poles in Adams County, while smaller hail piled up like snow in some parts of the Denver area.