On Thursday, there were 27 reports of tornadoes, said CNN meteorologist Brandon Miller. The exact number will be released by the National Weather Service when investigating the damage.
A reported tornado hit a company in Pella, some 40 miles from Des Moines, and sent at least seven people from the Vermeer Corporation hospitalized with injuries.
The company, which manufactures industrial and agricultural equipment, had great damage, Vermeer managing director Jason Andringa said.
Several More Injured People in Marshalltown
In Marshalltown, a city of about 27,000, about an hour northeast of Des Moines, 10 people suffered injuries after a tornado hit the area.
None of the patients In critical condition, hospital spokeswoman Laura Rainey said.
Julie Owen from Des Moines visited her daughter in Marshalltown when the tornado struck.
She was not in the area where the tornado struck, but went into town to help fetch her granddaughters.
"It was bad, I've seen a lot of tornadoes (in the past)." She said. "It's not like the whole city is destroyed, but Downtown, a city of this size, was something else."
Photos of Billie Blocker Rice show damage to buildings on the north side of the city.
"Devastated to see the destruction caused by today's heavy storms and tornadoes Praying for all concerned Iowans & for the emergency management crews tonight, Governor Kim Reynolds tweeted Thursday.
Bondurant Homes Damaged
Trees collapsed into streets Houses are missing many shingles, a large industrial building lacks wall sections and debris over the vehicles in the parking lot.
"Everyone is advised to stay away from downtown Marshalltown until further notice," city councilor Jessica Kinser said in a statement. "We also demand that people stay out of cell lines when they are not needed to make emergency calls."
CNN's Hollie Silverman, Sheena Jones, Abbie Lane and Jamiel Lynch have contributed to this report.