(T0) Light Tornado: 17-24 m/sec., 39-54 mph. Loose light litter raised from ground-level in spirals. Tents, marquees seriously disturbed; most exposed tiles, slates on roofs dislodged. Twigs snapped; trail visible through crops.
(T1) Mild Tornado: 25-32 m/sec., 55-72 mph. Deckchairs, small plants, heavy litter made airborne; minor damage to sheds. More serious dislodging of tiles, slates, chimneys pots. Wooden fences flattened. Slight damage to hedges and trees.
(T2) Moderate Tornado: 33-41 m/sec., 73-92 mph. Heavy mobile homes displaced, light caravans blown over, garden sheds destroyed, garage roofs torn away, much damage to tiled roofs and chimney stacks. General damage to trees, some big branches twisted or snapped off, small trees uprooted.
(T3) Strong Tornado: 42-51 m/sec. 93-114 mph. Mobile homes overturned/badly damaged; light caravans destroyed; garages, outbuildings destroyed; house roof timbers considerably exposed. Some of the bigger trees snapped or uprooted.
(T4) Severe Tornado: 52-62 m/sec., 115-136 mph. Mobile homes destroyed; some sheds airborne for considerable distances, entire roofs removed from some houses or prefabricated buildings; roof timbers of stronger brick or stone homes completely exposed; possible collapse of gable ends. Numerous trees uprooted or snapped.
(T5) Intense Tornado: 62-72 m/sec., 137-160 mph. Motor cars levitated; more serious building damage than for T4, yet housewalls usually remaining; the weakest, old buildings may collapse completely.
(T6) Moderately-devastating Tornado: 73-83 m/sec., 161-186 mph. Heavy motor vehicles levitated; strong houses lose entire roofs and perhaps also a wall; more of the less-strong buildings collapse.
(T7) Strongly-devastating Tornado: 84-95 m/sec., 187-212 mph. Frame houses completely demolished; some walls of stone or brick houses beaten down or collapsed; steel-framed warehouse-type buildings may buckle slightly Locomotives thrown over. Noticeable de-barking of any standing trees by flying debris.
(T8) Severely-devastating Tornado: 96-107 m/sec., 213-240 mph. Frame houses and their contents dispersed over big distances; most other stone or brick houses irreparably damage; steel-framed buildings buckled; motor cars hurled great distances.
(T9) Intensely-devastating Tornado: 108-120 m/sec., 241-269 mph. Many steel-framed buildings badly damaged; locomotives or trains hurled some distances. Complete debarking of any standing tree-trunks.
(T10) Super Tornado: 121-134 m/sec. or more, 270-299 mph or more. Entire frame houses and similar buildings, lifted from foundations and carried some distances. Steel-reinforced concrete buildings may be severely damaged.