What is a tornado?
The word “tornado” comes from the Latin tornare, which means to “spin”.
A tornado is a very violent gale characterized by a funnel shaped gyrating cloud. It is generated during thunder storms (or, sometimes, as a result of a hurricane) and is produced when cold air extends over a layer of hot air, forcing hot air to elevate quickly. Damage caused by a tornado is the result of speeding wind and rubble dragged by the wind. The tornado season is usually from March to August, although tornadoes may occur at any time of the year. They are usually produced during the afternoons and nights: More than 80 percent of all tornadoes are triggered between the afternoon and midnight.
A tornado’s width may vary from thirty centimeters to almost a couple of kilometers. Wind speed inside a tornado is not exactly known, but it is estimated to reach up to 500 km/h. Thus, it is not strange that such speed is able to drag trees, cars, houses, etc. Fortunately, only 2% of tornadoes go over 300 km/h.
Most tornadoes are around 50 meters wide, travel at 50 km/h and last only a couple of minutes.
When a tornado threats, people need a safe place to go and time to get there. Even with weather technology, warning times can be short or impossible sometimes. Lives are saved when people receive and understand the warning, know what to do and know the safest place to go.
TORNADO FORMATION
As explained in the Hurricane section, Tornadoes are generated in the walls of a hurricane, since they face two opposed forces: The centrifugal force of the wind that turns in circles (due to the influence of earth’s rotation movement and the physical trend of liquids and gas to form these whirlwinds when subject to “turbulence”) and the suction force it generates drawing hot air in and making it rise to the coldest areas where, when cooling, generate more suction and “pulling” that perpetuate the phenomenon. These rotating masses of air are called, in technical language, mesocyclones.
A more technical explanation of the phenomenon, recently obtained after monitoring several tornadoes, is given by the constant fact that, at least in tornadoes in en US, they always coincide with three types of winds. A ground wind, coming from the Southeast, another wind at 800 m, coming from the South, and a third wind over 1,600 m coming from the Southwest. When these forces collided, air rotation began.
When the air at the highest areas cooled, clouds with electrostatic charges were formed, producing a large amount of thunder and lightning, without necessarily being related to the tornado’s magnitude. This water coldness can also produce large hail in the tornado’s proximity, which should be a warning sign.
The typical gyrating “funnel” is not always visible, formed by dust, water and clouds, but an equally destructive, more atypical formation may take place.
This rotation (called cyclonic, which means gyrating), happens counterclockwise (seen from above) in the northern hemisphere (US, India, Bangladesh) and clockwise in the Southern hemisphere.
Information about tornado:
• They can develop quickly, with Little or no warning.
• They can be almost transparent until dust and garbage are picked up by the funnel shaped cloud.
• The average tornado moves from the Southeast to the Northeast, but they are known to be able to move in any direction.
• The average travel speed of a tornado is 30 MPH, but may vary from stationary to 70 MPH.
• Tornadoes may come along tropical storms and hurricanes moving inland.
• “Waterspouts” are tornadoes forming over water.
• Tornadoes are more frequent at the east of the Rocky Mountains during the spring and summer months.
• The highest tornado season in the southern states is from March to May; in the northern states, it is from the Spring to the beginning of the Summer.
• Tornadoes have more chances of happening between 3 pm and 9 pm, but can happen at any moment.
