Tornadoes| National Geographic

Tornadoes are big funnel-shaped clouds that can rip through a community and leave a wake of destruction. They can form in seconds, change direction in a heartbeat, and their devastation can last a lifetime. Exactly how and why tornadoes occur is still a bit of a mystery, but an indication that one is forming is a wall cloud. Fast-moving winds roll air below into a horizontal vortex above an opposing surface. Similar to a spinning top warmed by the Sun, buoyant air near the ground begins to lift a section of the horizontal vortex into a vertical position.

The vortex extends toward the ground as it picks up speed. Anything in its path can be ripped apart or thrown in the air. Upper-level winds tilt the rotating updraft, called a mesocyclone. This allows a storm to keep growing as warm air is sucked into the storm, away from the cool downdraft. The vortex spins like a top, sometimes up to 300 miles per hour. While some tornadoes move slowly, others can travel over the ground at speeds of over 110 miles per hour.

The widest tornado ever recorded, the May 2013 El Reno tornado in Oklahoma, was 2.6 miles across—that’s wider than Manhattan. Research has allowed us to identify the essential ingredients needed for twisters to form in the U.S.: warm, moist air typically from the Gulf of Mexico, cool air typically from Canada, and dry air typically from the Rockies. When these air masses collide, they create the perfect conditions for a tornado.

Nearly three-quarters of the world’s tornadoes occur in the United States, and the peak season is between May and June. A majority touch down in Tornado Alley, a section of the central United States. However, tornadoes have been recorded in all 50 states and on every continent except Antarctica.

Tornadoes are very dangerous, and you should never underestimate their power. The average time between a tornado warning and a strike is estimated at a mere 13 minutes, giving residents little time to seek shelter. On average, tornadoes kill 60 people every year in the United States.

The deadliest tornado in history was not in the United States but a tornado that ripped through Bangladesh in 1989, killing an estimated 1,300 people. We measure the amount of damage to land and property using the EF scale, which ranks tornadoes on six different levels—from zero, a heavy breeze that can uproot crops, to level five, enough wind to pick up a house.

It’s the desire to better understand them that sends scientists into the field year after year in search of answers that can hopefully save lives while putting theirs at risk.

• rip through /rɪp θruː/ (phrasal verb) – To move forcefully through something, causing damage.
  SYN: tear, slash
  Example: The tornado ripped through the small town, destroying homes and trees.

• leave a wake of /liːv ə weɪk əv/ (phrase) – To cause a trail or result of something (usually destruction or impact).
  SYN: leave behind, cause
  Example: The hurricane left a wake of devastation in the coastal regions.
• in a heartbeat /ɪn ə ˈhɑːrtbiːt/ (phrase) – Very quickly or instantly.
  SYN: instantly, immediately
  Example: He agreed to help in a heartbeat when he heard about the disaster.
• indication /ˌɪndɪˈkeɪʃn/ (n) – A sign or piece of information showing something might happen.
  SYN: sign, clue
  Example: The dark clouds were an indication that a storm was approaching.
• horizontal vortex /ˌhɔːrɪˈzɑːntl ˈvɔːrteks/ (n) – A spinning air current parallel to the ground.
  SYN: whirlwind, cyclonic flow
  Example: The horizontal vortex formed quickly before rising into a tornado.
• vertical /ˈvɜːrtɪkl/ (adj) – Standing or pointing straight up.
  SYN: upright, perpendicular
  Example: The wind lifted the horizontal vortex into a vertical position.
• tilt the rotating updraft /tɪlt ðə ˈroʊteɪtɪŋ ˈʌpdraft/ (phrase) – To cause the spinning upward air current to lean or incline.
  SYN: shift, incline
  Example: Upper-level winds tilted the rotating updraft, fueling the storm.
• cool downdraft /kuːl ˈdaʊndræft/ (n) – A downward rush of cool air.
  SYN: cold air current, downdraft
  Example: The cool downdraft brought a sudden chill to the area.
• twisters /ˈtwɪstərz/ (n) – Informal term for tornadoes.
  SYN: tornadoes, cyclones
  Example: Twisters are common in Tornado Alley during spring.
• touch down /tʌtʃ daʊn/ (phrasal verb) – To land or make contact with the ground.
  SYN: land, arrive
  Example:The tornado touched down in the open field before heading toward the town.
• underestimate /ˌʌndərˈestɪmeɪt/ (v) – To think something is less serious or important than it actually is.
  SYN: underrate, misjudge
  Example: People should never underestimate the power of a tornado.

• uproot /ʌpˈruːt/ (v) – To pull something out of the ground by its roots.
  SYN: displace, pull out
  Example: The strong winds uprooted trees across the neighborhood.

• 🌪 Tornadoes:
• Funnel-shaped storms, form in seconds, cause massive destruction.
• ⚙️ Formation:
• Strong winds → horizontal vortex → lifted vertically → tornado.
• 📍 Distribution:
  • 75% occur in the U.S., especially in Tornado Alley.
  • Peak season: May–June.
• 📏 Size & Speed:
  • Winds: Up to 300 mph.
  • Widest: El Reno (Oklahoma, 2013) – 2.6 miles wide.
• 💀 Impact:
  • Average: 60 deaths/year in the U.S.
  • Deadliest: Bangladesh (1989) – 1,300 deaths.
  • Warning time: Only 13 minutes.
• 📊 Measurement: EF scale from 0 (minor damage) to 5 (catastrophic).
• 🔬 Science: Scientists risk lives to improve predictions and save others.