TWISTER TWISTER : Also known as or . It is a violently rotating column of air that is in contact with both the surface of the earth and thunderstorm cloud. The term Tornado or Twister refers to the of wind, not the condensation cloud. It comes in many shapes and sizes, but they are typically in the form of a visible condensation funnel, whose Wind of Twister narrow end touches the earth and is often encircled by debris and dust. Most tornadoes have wind speed less than 180km/h, are about 75m across, and travel several kilometers before dissipating. Twister Stretch The most extreme tornadoes can attain wind speed of more than 500km/h,stretch more than 3km across, and stay on the ground for more than 100km. HOW A TWISTER FORMS : Tornadoes are among the most violent on Earth, with the potential to cause very serious damage. Step 1 : Step 2 : Tornadoes needs certain When the warm, moist air meet Cold, Heat condition to form - particularly cold dry air, it explodes upwards, Dry Air very intense or unseasonable puncturing the layer above. A heat. Warm, thunder cloud may begin to build. Warm, Due to this heat, the ground Moist Air A quickly develops - there Moist Air temperature increases; the may be rain, thunder and moist air heats and starts to rise. Courtesy by - BBC News lightning. Courtesy by - BBC News Step 3 : Step 4 : Upward movement of air can The vortex of winds varies in become very rapid. Winds from size and shape, and can be different directions cause it to hundreds of meters wide. A rotate. tornado can last from several A visible cone or funnel drops Cross Cross seconds to more than an hour out of the cloud towards the Wind Wind and may travel dozens of miles. Vortex ground. Courtesy by - BBC News Courtesy by - BBC News SCALE OF MEASUREMENT FOR TWISTER : Winds within the tornado may be so fast they cannot be properly measured. Instead, the Fujita damage scale is used to estimate speed Fujita Tornado Damage Scale F0 wind speed 0-117 kmph light damage : Some damage to chimneys, branches break off trees. F1 F2 F3 F4 F5 Wind Speed Wind Speed Wind Speed Wind Speed Wind Speed 119 - 180 kmph 180 - 253 kmph 253 - 332 kmph 332 - 418 kmph 418 - 512 kmph

Moderate Damage - Considerable Damage - Severe Damage - Devastating Damage - Incredible Damage - Cars blown off roads, Large trees snapped, Most trees uprooted, Well built buildings Cars thrown over 100 Mobile homes cars lifted off ground, heavy cars thrown, walls destroyed, large objects meters, strong buildings overturned mobile homes destroyed of homes destroyed thrown swept away Web : http://grapes-3.tifr.res.in Cosmic Ray Laboratory E-Mail : [email protected] TWISTER OTHER TWISTER - LIKE PHENOMENA : , , Fire Whirls and Steam Devil

GUSTNADO : DUST DEVIL : A gustnado is a specific type A Dust Devil resembles a of short - lived, low level tornado is that it is a vertical rotating cloud that can form swirling column of air. in a severe thunderstorm. However, they form under They are not connected with clear skies and are not a cloud base. stronger than the weakest They are formed when fast moving cold, dry outflow air tornadoes. from a thunderstorm is blown through a mass of They form when a strong stationary and warm air near the outflow boundary, convective updraft is formed resulting in a “rolling” effect. near the ground on a hot day. FIRE WHIRLS : STEAM DEVIL : A , is a A Steam Devil is a small, induced by a fire and weak whirlwind over often made up of flame or water(or sometimes wet ash. land) that has drawn It is also know as fire devil, into the vortex, thus fire tornado, firenado or rendering it visible. fire twister. They form over large lakes and oceans during Fire whirls may occur when intense rising heat and cold air outbreaks while the turbulent wind conditions combine to form waters is still relatively whirling eddies of air. warm. Often, fire whirls are created when a wildfire or They occur very rarely. firestorm creates its own wind, which can turn into a spinning vortex of flame.

DOWNBURTSTS : A downburst is a strong ground-level wind system that emanates from a single source, blowing in a straight line in all directions from that source. It may be confused with a tornado, but is actually quite different: in a downburst, winds are directed downwards and then outward from the surface landing point. Downbursts are often created on an area significantly rain-cooled air.

For More Information: Tornado in Bottle: Tornado Information https://www.youtube.com/watch?v=0 http://www.weatherwizkids.com/weat LfZFGcGc_I her-tornado.htm How Tornado Forms: http://www.sciencekids.co.nz/science http://www.eo.ucar.edu/kids/dangerw facts/weather/tornado.html x/tornado3.htm http://easyscienceforkids.com/all- http://downloads.bbc.co.uk/news/nol/ about-tornadoes/ shared/spl/hi/sci- http://en.wikipedia.org/wiki/Tornado nat/06/tornado/pdf/how_tornado_is_ formed.pdf

Web : http://grapes-3.tifr.res.in Cosmic Ray Laboratory E-Mail : [email protected] TWISTER DUST DEVIL @ GRAPES - 3 : Each year around summer season the dust devils are observed at GRAPES-3 experiment. Following are the dust devil encounters.

AFTER EFFECTS OF DUST DEVIL : The dust devils are powerful enough to uproot the assembled detectors and send it flying in the air.

A detector cover has been thrown in the A detector cover has been thrown in the A badly damaged detector with its cover air at around 100 m. height. air at around 60 m. height. smashed by dust devil

Detectors(60 kg.) tumbled and its covers 3 Detectors(100 kg. each) dislocated from Many Detectors tumbled and their covers tossed up at near by places its original mounting position all over the place

Web : http://grapes-3.tifr.res.in Cosmic Ray Laboratory E-Mail : [email protected]