The Southern Plains have long been thought of as Tornado Alley, but with recent activity creeping toward the Deep South, experts say it’s time to rethink what we know about America’s twister hotspot.

Tornadoes are among the most powerful and unpredictable storms on Earth. They usually form from large thunderstorms when the air in the atmosphere becomes unstable. Warm, humid air near the ground begins to rise quickly while cooler air above sinks and falls with rain or hail.

When a tornado warning is issued, knowing the safest place in your home to take shelter can mean the difference between life and death.

Parts of the Southern and Northeastern U.S. faced tornado threats this week. Scientists are trying to parse out the climate links in changing tornado activity.

An updated tornado warning was issued by the National Weather Service on Wednesday at 4:05 p.m. in effect until 4:15 p.m. for Bedford, Cambria and Somerset counties.

On Monday at 1:51 a.m. a tornado warning was released by the National Weather Service in effect until 2:30 a.m. for Monroe and Wilcox counties.