The following are facts about tornadoes from the FEMA website:

* They may strike quickly, with little or no warning.
* They may appear nearly transparent until dust and debris are picked up or a cloud forms in the funnel.
* The average tornado moves Southwest to Northeast, but tornadoes have been known to move in any direction.
* The average forward speed of a tornado is 30 MPH, but may vary from stationary to 70 MPH.
* Tornadoes can accompany tropical storms and hurricanes as they move onto land.
* Waterspouts are tornadoes that form over water.
* Tornadoes are most frequently reported east of the Rocky Mountains during spring and summer months.
* Peak tornado season in the southern states is March through May; in the northern states, it is late spring through early summer.
* Tornadoes are most likely to occur between 3 p.m. and 9 p.m., but can occur at any time.

Click on read more to learn how you can protect yourself from a tornado:

If you are in a structure (e.g. residence, small building, school, nursing home, hospital, factory, shopping center, high-rise building):

Go to a pre-designated shelter area such as a safe room, basement, storm cellar, or the lowest building level. If there is no basement, go to the center of an interior room on the lowest level (closet, interior hallway) away from corners, windows, doors, and outside walls. Put as many walls as possible between you and the outside. Get under a sturdy table and use your arms to protect your head and neck. Do not open windows.

If you are in a vehicle, trailer, or mobile home

Get out immediately and go to the lowest floor of a sturdy, nearby building or a storm shelter. Mobile homes, even if tied down, offer little protection from tornadoes.
The outside with no shelter

If you are outside:

Lie flat in a nearby ditch or depression and cover your head with your hands. Be aware of the potential for flooding.

Do not get under an overpass or bridge. You are safer in a low, flat location.

Never try to outrun a tornado in urban or congested areas in a car or truck. Instead, leave the vehicle immediately for safe shelter.

Watch out for flying debris. Flying debris from tornadoes causes most fatalities and injuries.