Two of the fatalities were reported in McClain County, while the third occurred in a nearby county, Sheriff‘s Deputy Scott Gibbons said.
Rescue workers had finished their search for trapped people after a twister roared through the farming county of 40,000 on Wednesday evening, he said.
“We’re going to have quite a few homes that are completely destroyed throughout our county,” Gibbons said.
A survey crew near Cole, a rural town of 600 about 30 miles (48 km) south of Oklahoma City, found a home with damage caused by a EF-3 tornado, the National Weather Service said in a Tweet. An EF-3 is the third strongest tornado on the Enhanced Fujita scale, packing winds of up to 165 miles (265 km) per hour.
Video footage and photographs from Cole and other parts of the county showed leveled homes and debris fields, power poles strewn across roadways and uprooted trees laying in yards.
One family of four sheltered under a mattress in their mud room as the tornado flattened their home, the National Weather Service reported.
The tornado was part of a swarm of 18 twisters sighted by spotters in Oklahoma, Iowa and Kansas, the National Weather Service (NWS) said.
The dangerous weather was expected to continue throughout the afternoon and evening on Thursday with the possibility of more tornadoes, along with scattered severe thunderstorms and large hail in the forecast for northeast Kansas into southwest Iowa, the NWS said.
Almost 16,000 customers in Oklahoma remained without power as of midday on Thursday due to the storms, according to the website poweroutage.us.
The activity comes weeks after a tornado tore through southeastern Missouri, killing five people. A previous bout of thunderstorms also unleashed a tornado last month that devastated the town of Rolling Fork, Mississippi, destroying many of the community’s 400 homes and killing 26 people.