Twisters that tore through Union County, Missouri killed 6 people. One couple survived against incomprehensible odds in a trailer obliterated by the storm.

A storm system crossing the U.S. threatens to unleash tornadoes Friday in the Mississippi Valley, blizzards in the northern Plains and dry conditions in Texas and Oklahoma that pose a wildfire risk.

Iowa's Department of Public Safety says there could be many more people injured. Other severe weather events, such as floods and snowstorms, are expected in other parts of the country.