Tornadoes ripped through Alabama and killed at least seven people, including five at a high school where students became pinned under debris when a roof collapsed, state officials said.
As night fell Thursday, crews dug through piles of rubble beneath portable lights at Enterprise High School, looking for other victims.
"The number could very well increase as the search effort continues through the night," state emergency management spokeswoman Yasamie Richardson said.
The burst of tornadoes was part of a larger line of thunderstorms and snowstorms that stretched from Minnesota to the Gulf Coast. Authorities blamed a tornado for the death of a 7-year-old girl in Missouri, and twisters also were reported in Kansas.