Although there is no guaranteed safe place during a tornado, some locations are better than others. By following these suggested safety tips, you can increase your chances for survival.
At Home
Get to shelter immediately. AVOID WINDOWS. Flying glass can injure or kill. Don't open windows. Houses don't "explode" and allowing strong wind in can do damage or cause injury.
The safest place in the home is the interior part of the basement, preferably under something sturdy like a table. Stay out from under heavy objects like pianos or refrigerators in the floor above.
If you have no basement, go to an inside room on the lowest floor, like a closet, hallway, or bathroom with no windows.
For added protection, get under something strong, like a workbench or heavy table. If possible, cover your body with a blanket or sleeping bag and protect your head with anything available, even your hands.
Mobile Home
Do not stay in a mobile home during a tornado. Even homes with a secure tie down system cannot withstand the force of tornado winds.
Plan ahead. Make arrangements to stay with friends or neighbors who have a basements. Go there if a tornado watch is issued.
If a tornado warning is given, leave your mobile home and seek shelter nearby. Lie flat in a ditch or ravine and put your arms over your head. Don't take shelter under your home.
Encourage your mobile home community to build a tornado shelter if you live in a tornado-prone area.
On the Road
The least desirable place to be during a tornado is in a motor vehicle. Cars, buses, and trucks are tossed easily by tornado winds.
Do not try to outrun a tornado in your car.
If you see a tornado, stop your vehicle and get out. Seek shelter away from the car in a nearby ditch or ravine. Don't take shelter under your vehicle. Lie flat in a ditch or ravine and put your arms over your head.
Long Span Buildings
Long span buildings are dangerous. The entire roof structure is supported solely by the outside walls. Inside walls are usually false or non-load bearing walls.
If you are caught in a open building like a shopping mall, civic center, indoor pool, theater, or gymnasium during a tornado, stay away for windows. Get into the restroom, if possible. In larger buildings the restrooms are usually made from concrete block. Besides having four walls and plumbing holding things together, metal partitions help support any falling debris.
If there is not time to go anywhere, seek shelter right where you are. Try to get up against something that will support or deflect falling debris. For instance, in a department store, get up against heavy shelving or counters. In a theater, get under seats. Remember to protect your head.
Schools, Hospitals, Nursing Homes, and Office Buildings
Extra precautions are needed in these structures. Not only is there a large concentration of people in a small area, but these buildings usually have large amounts of glass on the outside walls.
Get into the innermost portions on the lowest floor possible.
Avoid windows, glass doorways, and auditoriums and cafeterias not protected by overhead floors and rooms.
Do not use elevators; the power may go off and you could become trapped.
Protect your head and make yourself a small target as possible by couching down.
In the Open
If you are caught outside during a tornado and there is no underground shelter immediately available, lie in a gully ditch, or low spot in the ground. Protect your body and head with anything available. Do not go into a grove of trees or under a vehicle.
Emergency services personnel are usually on the scene quickly after a tornado. Keep your family together and wait for help to arrive. Listen to the radio for information about disaster relief and volunteer agencies.
If you are outside, don't go into damaged buildings; they may collapse completely. Wait for help to search for others.
If your home appears undamaged, check carefully for gas or other utility line breaks. If the lights are out, use a flashlight only; do not use a match, lighter, or any open flame.
Fujita - Pearson Tornado Scale

F-0: 40-72 mph, chimney damage, tree branches broken
F-1: 73-112 mph, mobile homes pushed off foundation or overturned
F-2: 113-157 mph, considerable damage, mobile homes demolished, trees uprooted
F-3: 158-205 mph, roofs and walls torn down, trains overturned, cars thrown
F-4: 207-260 mph, well-constructed walls leveled
F-5: 261-318 mph, homes lifted off foundation and carried considerable distances, autos thrown as far as 100 meters