At least one person was killed when a tornado slammed into the town of Tushka, Oklahoma, about 135 miles south of Tulsa.
Another person was killed as a twister ripped through a trailer park in Buffalo, in southwest Missouri.
At least 13 people are injured in Buffalo.
Some of the worst damage is in towns such as Branson, Missouri and Harveyville, Kansas.
Kansas Governor Sam Brownback has issued a state of emergency for Wabaunsee County where Harveyville is located.
Local emergency officials in Branson say the storms damaged some of the town's famed music theaters as well as a Walmart, a Taco Bell, a pizza shop and at least one hotel.