A powerful storm system will bring several life-threatening weather hazards to Tennessee starting Wednesday night, including the threat of flash flooding and tornados, warns the National Weather Service.

When a warning is issued, take action. This means tornado conditions are imminent and have been spotted either by someone on the ground or by radar. Warning areas are typically smaller than those within a watch and are issued for a shorter time period, typically about 15 minutes.

"TAKE COVER NOW! Move to a basement or an interior room on the lowest floor of a sturdy building," the tornado warning said. "Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris."

At 2:24 p.m. on Tuesday, the NWS Sacramento CA issued a tornado warning in effect until 3:15 p.m. for Nevada and Yuba counties.

A tornado warning means a tornado has been spotted or indicated by the radar. Stay in your safe place until the threat of the tornado has passed.

The warning was in place for Dale and Henry counties.

People in the warning areas are urged to seek shelter inside a sturdy building and stay away from windows until the threat is over.

It wasn’t long after students at Dothan Preparatory Academy took shelter that a tornado suddenly touched down around the campus on Monday afternoon, causing significant damage.

There is a high risk for a nocturnal tornado outbreak in the South tonight. Very large hail and damaging wind gusts are forecast as residents plan for a potentially deadly night of severe thunderstorms.