Tornado

A tornado is an area of fast spinning winds made by a strong rotating thunderstorm that touches the ground. Tornadoes can be anywhere between a few hundred feet wide and several thousand feet wide. Wind inside the tornado can be very fast, though winds outside or around the tornado can almost as fast. This makes tornadoes very dangerous, and hard to tell where the edge of the tornado is. Tornadoes are especially dangerous to people in cars, trucks, buses or mobile homes and about 60 people are killed by tornadoes every year. The word "tornado" might come from the Spanish word tronada (thunderstorm), which comes from the word tronar (to thunder).

Tornadoes are very destructive – they can tear houses to pieces in seconds. Cars and trucks may be thrown away and often leave people homeless. Tornadoes can be caused by spinning winds inside of a storm. Nearly three quarters of the world's tornadoes happen in the United States. However, they can happen anywhere. The strongest tornadoes were found to have winds around 300 mph, though most tornadoes have winds between 60 and 100 miles per hour.

Tornadoes mostly happen during rotating thunderstorms called supercell storms. These supercells have a rotating updraft, called a mesocyclone, which can lead to them being very strong and dangerous, often producing large and damaging hail and/or damaging winds. 

Tornadoes are ranked on the Enhanced Fujita scale, from EF0 to EF5. EF0 is used for tornadoes that cause the least amount of damage, and EF5 is used for tornadoes that cause the most amount of damage. Before 2007, tornadoes used to be rated on the Fujita scale, a now outdated scale made by tornado scientist Ted Fujita, often called the father of tornado science. Fujita was one of the first people to make detailed research on tornadoes and discovered many things about tornadoes. He made the Fujita scale in 1971.

Tornadoes can happen in nearly any part of the world. In the United States, a tornado has happened in every state. The middle part of the United States is nicknamed "Tornado Alley" because of the number of tornadoes there. 

Other tornado-like phenomena that exist in nature include the gustnado, dust devil, fire whirls, and steam devil; downbursts are frequently confused with tornadoes, though their action is not similar.

 Characteristics 
 Condensation funnel 
The very low pressure caused by the high wind speeds and rapid rotation can causes water vapor in the air to condense into a visible condensation funnel. Many times, the condensation funnel of a tornado does not show the full size of a tornado. A tornado may have a small condensation funnel but still have tornado-force winds a mile away, meaning they can be extremely dangerous to people caught unprepared, including drivers and even experienced storm chasers.

 Tornado family 
A single storm may produce multiple tornadoes and mesocyclones. Tornadoes produced from the same storm are referred to as a tornado family. Sometimes multiple tornadoes from different mesocyclones can be on the ground at the same time. Families like these can lead to long swaths of damage, like with the 2021 Quad-State tornado family.

Occasionally, several tornadoes are spawned from some large weather event spanning multiple states. If there is little to no break in their activity, this is considered a tornado outbreak, although there are various definitions. A period of several successive days with tornado outbreaks in the same general area (spawned by multiple weather systems) is a tornado outbreak sequence, occasionally called an extended tornado outbreak. 148 tornadoes struck on the same day in April 1974. Many towns in the midwestern United States and Canada were destroyed with more than 300 people losing their lives. 

Damage scale
+ Tornado rating classifications F0EF0 F1EF1 F2EF2 F3EF3 F4EF4 F5EF5 Weak Strong Violent  Significant  Intense

The Fujita scale and the Enhanced Fujita Scale rate tornadoes by how much damage they cause. The Enhanced Fujita (EF) Scale was an update to the older Fujita scale. The updated scale uses engineered wind estimates and has better damage descriptions. The EF Scale was designed so that a tornado rated on the Fujita scale would get the same numerical rating, and was used in the United States since 2007. An EF0 tornado will probably damage trees but not big buildings, whereas an EF5 tornado can rip well-built buildings off their foundations leaving nothing left and even permanently damage big skyscrapers.

In the United States, 80% of tornadoes are EF0 and EF1 (equivalent to T0 through T3) tornadoes. Less than 1% of tornadoes are violent tornadoes (EF4 or EF5, or equivalent to T8 or stronger).

Due to a change in the way tornadoes were rated after 2013, no tornadoes ended up getting an EF5 rating until 2025, where a large tornado struck near Enderlin, Nebraska, sending train cars flying through the air. A survey by the Northern Tornadoes Project found that winds well above the EF5 threshold would be needed to do the damage done.

 Tornado watches/warnings/emergencies 
A "tornado watch" is given when the weather conditions look like a storms capable of making tornado could form. A 'PDS (Particularly Dangerous Situation)' watch is given when a likely tornado outbreak is to start, many strong tornadoes will form in the area, or an ongoing tornado outbreak is in the works in the area. A "tornado warning" is issued over a small area (usually the size of a city or a portion of a county) if meteorologists think a tornado could form or is on the ground, usually based off of radar or if a tornado has been reported by someone. Tornado emergencies can be issued if a likely strong or intense tornado is about to hit an area with a lot of people in it (especially cities in Tornado Alley), a tornado has been spotted, and the tornado is expected to cause deaths or severe harm.

Myths and misconceptions
It is often thought that opening windows will lessen the damage caused by a tornado. While there is a big drop in atmospheric pressure inside a strong tornado, it is unlikely that the pressure drop would be enough to cause the house to explode. Opening windows may actually increase the tornado's damage. A violent tornado can destroy a house whether its windows are open or closed.
Another common misconception is that highway overpasses provide adequate shelter from tornadoes. Due to the Venturi effect, tornadic winds are stronger in the small space of an overpass. In the 1999 Oklahoma tornado outbreak of May 3, 1999, three highway overpasses were directly hit by tornadoes. At each of the three places there was a death, along with many life-threatening injuries. By comparison, during the same tornado outbreak, more than 2000 homes were completely destroyed, with another 7000 damaged, and yet only a few dozen people died in their homes.

There are areas which people believe to be safe from tornadoes, whether by being in a city, near a major river, hill, or mountain, or even protected by supernatural forces. Tornadoes have been known to cross major rivers, climb mountains, hit valleys, and have damaged several city centers. As a general rule, no area is safe from tornadoes, though some areas are more likely to be hit than others.

 Safety tips 
To keep safe in a tornado, here are some tips people can follow:
 Go to the lowest floor of the building. Stay close to the center of the building and away from windows, for example, a bathroom with no windows and get into the bathtub.
 Find a piece of strong furniture or a mattress to go under or hide in a closet and wait until it is over.
 If inside a school, do not'' go to the gymnasium or any other place that has a high ceiling. Squat near the wall, placing the hands on the back of the head.
 If shelter is not available, find the lowest, most protected ground and cover the head with the hands.
 Do not drive if a tornado may be on the ground. If a person finds themselves in their car, they should position their head above the steering wheel, and cover themselves up. Hail, high winds, and heavy rainfall may make driving very dangerous.
 Do not seek shelter underneath an underpass or a bridge, as winds can increase under a bridge.

Related pages
 Waterspout
 Steam devil
 Tornado drill

 References 

 Other websites 

 Natural Disasters - Tornado 
 Tornadoes