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Tornadoes: Formation, Classification, Tracking, EF Scale

Tornadoes are violent, rotating columns of air that extend from a thunderstorm to the ground. They are among the most destructive weather phenomena, capable of causing significant damage and loss of life. Understanding how tornadoes form, how they are classified, and how they are tracked is essential for predicting and mitigating their impact. The Enhanced Fujita (EF) Scale is used to classify tornadoes based on the damage they cause, helping meteorologists estimate wind speeds and assess the severity of each event. This knowledge is crucial for improving weather forecasts, issuing timely warnings, and protecting communities in tornado-prone regions.

Figures (10)

U. S. annual count of confirmed tornadoes. The count uptick in 1990 is coincident with the introduction of doppler weather radar.
Schematic of a supercell's components
Wind shear (red) sets air spinning (green).
The updraft (blue) 'bends' the spinning air upwards.
The updraft starts rotating with the spinning column of air.
Structure of a supercell. Northwestward view in the Northern Hemisphere
Diagram of a supercell in the Northern Hemisphere from above. RFD: rear flank downdraft, FFD: front flank downdraft, V: V-notch, U: Main Updraft, I: Updraft/Downdraft Interface, H: hook echo
Radar reflectivity map
Tornadoes in the US, 1950–2013, highest F-scale on top, source NOAA Storm Prediction Center.
A tornado near Anadarko, Oklahoma, 1999. The funnel is the thin tube reaching from the cloud to the ground. The lower part of this tornado is surrounded by a translucent dust cloud, kicked up by the tornado's strong winds at the surface. The wind of the tornado has a much wider radius than the funnel itself.

They form when warm, moist air rises and meets cooler, drier air, creating instability. This causes air to spin and tighten, forming a funnel. It ranges from EF0 (weakest) to EF5 (strongest).

Meteorologists use this scale to estimate wind speeds and determine the tornado's severity. Tracking tornadoes involves radar and ground reports to warn people in their path. Students should picture a tornado as a spinning, narrow tube of air that can cause extreme damage as it moves across the ground.

Key Points

  • A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud, often visible as a funnel-shaped cloud.
  • A supercell is a type of thunderstorm characterized by a deep, persistently rotating updraft (mesocyclone) and is capable of producing severe weather, including tornadoes.
  • A mesocyclone is a mid-level rotation within a supercell thunderstorm, typically 2 to 6 miles in diameter, that can lead to the formation of tornadoes.
  • A tornado funnel is the visible, cone-shaped condensation cloud that extends from the base of a cumulonimbus cloud to the ground, representing the rotating column of air in a tornado.
  • The Enhanced Fujita scale is a system used to estimate the intensity of tornadoes based on the damage they cause to structures and vegetation, incorporating 28 damage indicators and degrees of damage for each indicator.
  • EF0 is the lowest rating on the Enhanced Fujita scale, indicating a tornado with winds between 65 and 85 mph that causes light damage, such as broken tree branches and minor roof damage.

Terms

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Sources & licensing(4)