1:87 Scale

The TORRO tornado intensity scale (or T-Scale) is a scale measuring tornado intensity between T0 and T10. more...

Home
Beanies
Construction Toys & Kits
Creative Toys/ Activities
Diecast & Vehicles
Educational Toys
Electronic Pets
Fast Food/ Cereal/ Sweets...
Games
Jigsaws & Puzzles
Model Kits
Aircraft (Military)
Aircraft (Non-Military)
Boats & Ships
Cars
Character Figures/ Animals
Military
1:100 Scale & Smaller
1:25 Scale & Larger
1:32 Scale
1:35 Scale
1:48 Scale
1:72 Scale
1:76 Scale
1:87 Scale
Other Military
Monsters
Motorcycles
Other Model Kits
Paints/ Accessories
Rockets
Scenery/ Props/ Buildings
Science Fiction
Space
Superhero
Trucks
Wooden/ Matchstick Kits
Other Toys & Games
Outdoor Toys & Activities
Pre-School/ Young Children
Radio-Controlled
Scalextric & Slot Car
Soft Toys/ Stuffed Animals
Steam
TV & Film Character Toys
Toy Soldiers
Vintage/ Classic Toys
Wargames & Role-Playing

It was developed by Terence Meaden of the Tornado and Storm Research Organisation (TORRO), a meteorological organisation in the United Kingdom, as an extension of the Beaufort scale.

The scale was tested from 1972-1975 and was made public at a meeting of the Royal Meteorological Society in 1975. The scale sets T0 as the equivalent of 8 on the Beaufort scale and is related to the Beaufort scale by the formula:

B = 2 (T + 4)

and conversely:

T = (B/2 - 4)

The Beaufort scale is expressed by the formula:

v = 0.837 B^3/2 m/s

TORRO claims it also differs from the Fujita scale in the fact that it relies solely on wind speed for classification, where the Fujita scale relies on damage for classification, but in practice, damage is utilised in both systems to infer intensity. This scale is primarily used in the United Kingdom whereas the Fujita scale is the primary scale used in the United States, Europe (to a lesser extent), and the rest of the world.

The TORRO scale has more graduations which makes it arguably more useful for tornadoes on the lower end of the scale, however, such accuracy and precision are not always attainable in practice, and the damage descriptors are unclear on the upper end of the scale. It should be noted that in use, Fujita ratings often also have extra qualifications added ("minimal F2" or "upper-end F3 damage").

Tornadoes are rated after they have passed and have been examined, not whilst in progress. In rating the intensity of a tornado, both direct measurements and inferences from empirical observations of the effects of a tornado are used. Few anemometers are struck by a tornado, and even fewer survive, so there are very few in-situ measurements. Weather radar is used when available. Sometimes photogrammetry or videogrammetry estimates wind speed by measuring tracers in the vortex. Aerial and ground damage surveys of structures and vegetation are utilised, sometimes with engineering analysis. Also sometimes available are ground swirl patterns left in the wake of a tornado.

Most UK tornadoes are T6 or below with the strongest UK tornado being a T8. For comparison, the strongest detected winds in a United States tornado (during the 1999 Oklahoma Tornado Outbreak in Moore, Oklahoma) would be T11 using the formula:

v = 2.365 (T+4)^3/2 m/s

v = 8.511 (T+4)^3/2 km/h

v = 5.289 (T+4)^3/2 mph

v = 4.596 (T+4)^3/2 kts

where v is wind speed and T is TORRO intensity number.

Alternatively, the T-Scale formula may be expressed as:

Read more at Wikipedia.org