Search and rescue is underway after 2 are killed in Oklahoma and more than a dozen tornadoes reported in 3 states

 (CNN) -- At least two people were killed by a severe round of storms in Oklahoma as more than a dozen tornadoes reportedly struck across three states Wednesday evening, leaving some residents trapped and thousands in the dark.

The deaths were reported in Cole, where the tally of fatalities and injuries could climb as search-and-rescue efforts continue and damage assessments are underway, Deputy Scott Gibbons with the McClain County Sheriff's Office told CNN.

First responders have also gotten reports of people trapped in shelters, Gibbons said. Search teams are facing the challenge of navigating roads littered with downed power lines and debris, he added. Systematic searches were being conducted across a 10-mile path, he said.

The same system that spawned severe storms Wednesday is heading east Thursday, bringing a severe storm threat for more 50 million people from Texas to Wisconsin as rain, hail, damaging winds and some tornadoes are possible.

Wednesday's storms were reported across Oklahoma, Kansas and Iowa, with Oklahoma appearing to be the hardest hit. About 20,000 homes and businesses in the state were without power Thursday morning.

A reported tornado in Cole, a town of more than 600 people about 30 miles south of Oklahoma City, appears to have been one of the most significant.

Barry Harbison, who lives in Cole, said it felt like a roller-coaster when the storm lifted his trailer home off the ground and tossed it while he was stuck in it.

"I stayed in the bathroom and (the storm) picked up the whole trailer and moved it," Harbison told CNN affiliate KOCO.

The National Weather Service in Norman, Oklahoma, plans to survey Cole, Shawnee and the Etowah-Pink-Stella area Thursday.

In addition to nine reports of tornadoes in Oklahoma, four tornado reports were recorded Iowa and three in Kansas on Wednesday. Of those reports, two tornadoes in Iowa and one in Kansas have been preliminarily confirmed.

'Blessed everybody is alive'

About 60 miles east of Cole, a large and very dangerous tornado was reported in Shawnee, a city of about 30,000 people in Pottawatomie County. The storm was moving erratically north of the city around 10 p.m. Wednesday, the National Weather Service in Norman said.

Shawnee Public Schools canceled classes Thursday, the district announced on Facebook.

More than 30 residents at Brookdale Senior Living, an assisted living facility in Shawnee, Oklahoma, were evacuated after the building's windows were blown out and water seeped inside, according to Shelee Stewart, the executive director.

"We've been blessed everybody is alive," Stewart told KOCO, noting there were no major injuries.

Stewart described the staff who helped guide residents to the bathrooms while the storm passed as "heroes," adding some had minor scratches.

As crews spread out in the county to respond to the storms, the Pottawatomie County emergency management agency warned residents not to leave their homes to observe the damage, noting that hinders response efforts.

"There is tremendous amounts of ponding on areas storms have come through so please do not drive through the water!" the agency said.

"Our county was hit hard and it will take a while for every area to be checked," the agency later said.

"If you can, check on your neighbors, but be mindful of potential gas leaks and possibly downed power lines," Shawnee Police said Wednesday evening in a Facebook post.

Oklahoma Baptist University in Shawnee also canceled classes Thursday and Friday after urging students to avoid being outdoors. No injuries were reported, but the campus was significantly damaged, the university said.

"Authorities are advising students to stay in their housing units through the night," due to downed power lines and scattered debris, the school said.