The word "tornado" comes from the Latin tonare, meaning "to thunder." The Spanish developed the word into tornear, to turn or twist. These are good descriptions of tornadoes, which are formed by rotating or twisting air. This is why they are also called twisters or cyclones.

A tornado is powerful column of winds spiraling around a center of low atmospheric pressure. It looks like a large black funnel hanging down from a storm cloud. The narrow end will move over the earth, whipping back and forth like a tail. The winds inside a tornado spiral upward and inward with a lot of speed and power. It crates an internal vacuum that then sucks up anything it passes over. When the funnel touches a structure, the fierce winds have the ability to tear it apart.

The winds inside a twister can spin around at speeds up to 500 miles an hour, but usually travels at roughly 300 miles an hour. This makes the tornado the most dangerous storm known to mankind. Because of the earth’s unique weather system, twisters rotate counterclockwise in the Northern Hemisphere and move eastward. They rotate clockwise in the Southern Hemisphere. Tornadoes also often come with hailstorms.

Thunderstorm develop in warm, moist air in advance of eastward-moving cold fronts. These thunderstorms often produce large hail, strong winds, and tornadoes. Tornadoes in the winter and early spring are often associated with strong, frontal systems that form in the Central States and move east. Occasionally, large outbreaks of tornadoes occur with this type of weather pattern. Several states may be affected by numerous severe thunderstorms and tornadoes. During the spring in the Central Plains, thunderstorms frequently develop along a "dry-line," which separates very warm, moist air to the east from hot, dry air to the west. Tornado-producing thunderstorms may form as the dry-line moves east during the afternoon hours. Along the front range of the Rocky Mountains, in the Texas panhandle, and in the southern High Plains, thunderstorms frequently form as air near the ground flows "upslope" toward higher terrain. If other favorable conditions exist, these thunderstorms can produce tornadoes.

Knowing what to do when you see a tornado, or when you hear a tornado warning, can help protect you and your family. During a tornado, people face hazards from extremely high winds and risk being struck by flying and falling objects. After a tornado, the wreckage left behind poses additional injury risks. Although nothing can be done to prevent tornadoes, there are actions you can take for your health and safety.

Learn about the tornado warning system of your county or locality. Most tornado-prone areas have a siren system. Know how to distinguish between the siren's warnings for a tornado watch and a tornado warning. A tornado watch is issued when weather conditions favor the formation of tornadoes, for example, during a severe thunderstorm.

During a Tornado watch:

• Stay tuned to a local radio or TV station or National Oceanographic and Atmospheric Administration (NOAA) Weather Radio for further weather information.
• Watched the weather and be prepared to take a shelter immediately if the condition worsen.
• A Tornado warning is issued to watch when a tornado is coming, the tornado funnel is sighted or indicated by a weather radar.
  

Variations of Tornado Some tornado may form during the early stages of rapidly developing a thunderstorms. This is the type of tornadoes is a bit common along the front of the Rocky Mountains, the Plains, and the Western States. Tornadoes may appear nearly transparent until the dusty and debris are pick up. Occasionally, two or more may happen at the same time.

Waterspout are weak tornadoes that form over a warm water. Waterspout are the most common along the Gulf Coast and Southeastern states. In Western United States , they  occur with cold late fall or late winter storms, during the time when you least expected on it. waterspout may move in homeland or inland that become tornado and may damage and injuries. This calamities that destroy our life.

• Before the thunderstorm may develop, a change in wind direction and an increase in speed with increasing height create an invisible, horizontal spinning effect in the lower atmosphere.
• Rising in air within the thunderstorm updraft tilts the rotating air from horizontal to vertical.
• An area rotations, 2-6 miles wide, now extending thru much of the storm. The most strong and violent tornadoes from within this area of strong rotation.

• March 12 in Philippines - a tornado touched down in South  Cotabato Province in the township of Tupi arounf 3:00 pm. The tornado destroyed 18 Hectares of Farmland, causing 8 million pesos in the damage of tornado during 15 minutes of existence.No structure were reported to have been damage and no one was injured.
• March 25 in Greece - a rare tornado touched down in Nea Manolada in Southwestern in  Greece.
  
• March 31 in India - a tornado struck the southern India state of Orissa in the Kendrapara's Kajkanika block, killing 15 people and injuring at least 200 people.