Factbox: Tornado survival tips

Some survivors of the tornadoes that killed more than 300 people in the southern United States this week narrowly escaped by seeking shelter in basements, closets and bathtubs -- and even in a freezer and a tanning bed.

Here are some safety tips from experts on what to do if a violent twister, dubbed "death tubes" by some, heads your way:

* If you are at home, find a reinforced, windowless area like an interior bathroom, closet, crawl space or hallway. Basements also provide good refuge, but stay away from outside walls. Try to crouch under the stairs or a heavy duty table to avoid falling debris.

* Be sure to protect your head and neck. "Put on a bicycle helmet or a football helmet," said Harold Brooks, a research meteorologist at the Storm Prediction Center of the National Oceanic and Atmospheric Administration. If you're in a bathtub, another option is to cover up with pillows, sofa cushions or a mattress.

* Do not open your windows, and stay away from them.

* If you are in a car in an urban area, don't try to outrun a tornado, the Federal Emergency Management Agency advises. If possible, seek shelter in a building. If you're outdoors with no nearby shelter, lie flat in a ditch or a depression. Cover your head with your hands. "Don't stay in your car and don't park it under an overpass," said Brooks.

* Stay away from trees and cars if you are outside.

* Avoid shopping malls, theatres and gymnasiums where the roof might only be supported by walls, the Harvard Medical School warns. "If there is no time to leave, get under a door frame or something else that could deflect falling debris," it advises.