How to shelter during a tornado if you don't have a basement

The deadly tornado outbreak that pummeled the South this weekend sent residents scrambling for a safe place to hunker down in the middle of the night.

Here's what you need to know about staying safe if you don't have a basement:

Tornado watch vs. tornado warning

A tornado watch means you should head toward a shelter, while a tornado warning signals that you should be in a shelter immediately.

The first tornado watch for western Mississippi was issued at 5:15 p.m. local time over the weekend. The first tornadoes hit Rolling Fork, Mississippi, at 7:57 p.m. local time.

What to do in high-rises and homes without basements

ABC News chief meteorologist Ginger Zee encourages people to not rely on their bathtub for safety.

Zee said she would move her family to the nearest rated shelter as soon as a tornado watch was issued if she didn't have an underground shelter. Not everyone, however, has easy access to internet or transportation.

For Rolling Fork, the closest rated tornado shelter is 17 miles west in Mayersville, Mississippi.

The safest community shelters are ones that are rated to withstand 200 mph winds.

In the wake of this weekend's tornadoes, storm chaser Edgar O'Neal saw "complete and utter devastation" in Rolling Fork, calling it one of the worst scenes he's witnessed.

"Houses gone, gas stations destroyed ... people wandering the street clearly in shock," O'Neal told ABC News.

"It's devastating and it's heart-shaking," Rolling Fork Mayor Eldridge Walker told ABC News. "Now we've got to put the pieces back together again."

ABC News' Max Golembo and Riley Finch contributed to this report.