Amateur video captured the tornado as it barreled down a six-mile trek that nearly cut the city of Joplin in half.
Search and rescue crews on Monday were searching for people who may be trapped under debris. But new storms bringing heavy rain and strong winds hampered search-and-rescue efforts, pelting the city with quarter-sized hail and sheets of rain.
An unknown number of people were injured, and officials said patients were scattered to any nearby hospitals that could take them.
Missouri's governor announced Monday evening that more survivors have been rescued from the rubble.
Aerials showed the destruction left behind by 200-mph winds. It only took 10 minutes for some 2,000 homes and businesses to be damaged or destroyed, including St. John's Regional Medical Center. The seven-story structure is now missing its two top floors. Hundreds of windows were blown out, as patients were evacuated.
"It was total chaos. The nurses were yelling to get away from the windows," said tornado survivor Sheila Harrington.
At least four people at the hospital were killed, Dr. Jim Roscoe said. He didn't know whether they were patients or staff.
Locals had about a 20-minute warning before the tornado ripped through, and people took cover where they could. As the power went out, shoppers inside a convenience store piled into a freezer.
When it was all over, the city of 50,000 was left stunned by the power of the monster storm. This is the nation's worst tornado since 1953 when a storm through Flint, Mich., also killed 116, according to the National Weather Service.
Officials expect the death toll from the tornado to rise. Crews found bodies in vehicles the storm had flipped over, torn apart and left crushed like empty cans. Triage centers and temporary shelters quickly filled to capacity. At Memorial Hall, a downtown entertainment venue, emergency workers treated critically injured patients.
Sunday's storm knocked down much of the city's south side. Officials estimate 25 to 30 percent of the city is damaged. The city's high school was wiped out, vehicles were tossed aside like toys and the Wal-Mart in the city collapsed, trapping hundreds of people.
Fire crews were working on spot fires because of some natural gas leaks. There were also breaks in water lines throughout Joplin, so water supply is a concern especially as pop up.
More tornadoes are expected across the nation's midsection through Wednesday.
The Associated Press contributed to this report.