Tornado!

Oklahoma weather
Tornado alley!

Live weather camera images from KJRH television, Tulsa, Oklahoma
Alternative Tulsa view

Today's weather forecast in Tulsa

Oklahoma has a wide range of weather conditions - in the last few years it has experienced severe storms, heavy rain and flooding and devastating tornadoes. Reload this page to view the changing weather as seen from automatic cameras on the KJRH TV tower in Tulsa, Oklahoma.
KJRH - Storm weather radar image

Tornado facts.....

  • The deadliest and most violent tornadoes in the world occur in the United States
  • Tornadoes are most common in Oklahoma and Texas - 'Tornado Alley'
  • The USA experiences some 100,000 thunderstorms each year - about 1,000 are severe enough to produce tornadoes
  • The best protection during a tornado is in an interior room on the lowest level of a building, preferably in a basement.
  • Torandoes strike with extreme velocities. Winds can uproot trees and buildings and turn normally harmless objects into deadly missiles. Mobile homes and caravans are particularly vulnerable to tornadoes.
  • Most tornado deaths occur when buildings collapse, people are hot by flying objects or are caught trying to escape the tornado in a car.
  • Tornadoes are most destructive when they touch the ground. Tornadoes will normally touch the ground for no more than 20 minutes.
  • Over 80% of tornadoes occur in the afternoon and early evening.
  • The UK experiences an average of 32 tornadoes each year - and has the highest frequency of reported tornadoes per unit area in the world
  • A tornado carved a swathe of destruction through the Sussex seaside town of Selsey on 7th January 1998. Damage was estimated at over £1 million.
  • Tornadoes are rated by the damage they cause - the Fujita scale
Tornadoes deliver some of the most devastating of severe weather effects. They form in the intense convectional cells of thunderstorms, reaching down to the ground with rotational wind speeds at hurricane force and beyond. Storms generating the most violent tornadoes occur in the USA in late spring as cold arctic air reaches south and interacts with warm moist air from the Caribbean, creating the conditions in which the violent motion can develop. The US National Weather Service delivers 'Tornado Watch' and 'Tornado Warnings' when atmospheric conditions are likely to create the intense storms that produce tornadoes - although the actual tornadoes themselves are extremely difficult to predict and forecast. Often the first warnings come from weather radar or from visual observations, offering little time for those in the likely track to prepare for potential disaster (62 deaths in the USA from January to June 1997 - the average annual death rate is 42).

When twisters form above water they create waterspouts - drawing water from the surface into the cloud above. Waterspouts quickly lose energy and collapse when the base moves over dry land - or over a ship. The water in the spout falls deluging the space below. Three waterspouts were observed in Southampton Water in mid June - the Solent is the area where they are most often reported.

Use the tornado links to find out the latest information, to find information on the formation and development of tornadoes and preparing for disaster. Storm chasing has become a popular activity in the USA and there are many reports and photographs of the most severe and violent events.

The 1998 tornado season

1998 will be remembered as one of the worst years for tornado damage across the USA. Already, by mid April, 102 people had lost their lives in tornado incidents across many states. Recent events in Tennessee, Georgia, Arkansas, Kentucky etc. have shown the power and dreadful destruction that tornadoes wreak. The strong El Niño effect has been suggested as a possible cause for this years toll - El Niño is now subsiding and with the approaching end of the normal tornado season there is hope that the death toll may now be over.

Normal US average annual death toll due to tornadoes: 42
January to June 1997: 62
January to April 1998: 103

Tornado links

The Fujita Scale of Tornado intensity
F scaleIntensityWind velocityDamage assessment
F0Gale tornado40 - 72 mphDamage to chimneys, tree branches broken, shallow rooted trees pushed over
F1Moderate tornado73 - 112 mphHurricane speeds: mobile homes pushed off foundations or overturned, surface peeled off roof, vehicles pushed off roads
F2Significant tornado113 - 157 mphConsiderable damage: roofs torn off houses, mobile homes demolished, trucks turned over, trees uprooted
F3Severe tornado158 - 206mphRoof and walls torn off well constructed houses, trains overturned, cars thrown off roads, most trees uprooted
F4Devastating tornado207 - 260mphWell constructed houses levelled, cars thrown
F5Incredible tornado261 - 318mphHouses lifted off foundations and disintegrate, cars thrown as much as 100m, bark stripped from trees, steel reinforced structures badly damaged
F6Inconceivable tornado319 + mphUnlikely to occur - but damage may be so extreme as to be difficult to relate to a tornado
Assessment of a tornado scale is done after the tornado has passed, according to the level and amount of damage left on the ground

Back to Severe Storms index

Page updated: January 12th 1999
This version: © St. Vincent College