At least 12 fatalities have been reported in Missouri, according to the Missouri State Emergency Management Agency. The deaths come as a massive storm system moving across the country unleashed winds that damaged buildings, whipped up deadly dust storms and fanned more than 100 wildfires.

An "outbreak" of tornadoes and severe thunderstorms is expected through Saturday night in Alabama, Mississippi, Louisiana, and other southern states.

We all hear the terms when there's a threat of severe weather. But what does each alert mean, and how does it affect you?

A tornado watch will be in effect for a large part of Alabama until 8 p.m. Saturday. It is a PDS watch, a rarely-issued watch that signifies a "particularly dangerous situation." National Weather Service All of Alabama faces the risk of seeing severe weather today,