Tornado Category / Damage Primer

 

 

A key point to remember is this: the size of a tornado is not necessarily an indication of its intensity. Large tornadoes can be weak, and small tornadoes can be violent.

 

Essentially, there is no functional difference in how tornadoes are rated. The old ratings and new ratings are cleanly connected with a linear formula. The only differences are adjusted wind speeds, measurements of which weren't used in previous ratings, and refined damage descriptors.

 

 

Enhanced F- Scale Number	Intensity Phrase	Wind Speed	Type of Damage Done
EF0	Light Damage	65-85 mph 105-125 km/h	Peels surface off roofs; some damage to chimneys; branches broken off trees; shallow-rooted trees pushed over; mobile homes pushed off foundations or overturned; sign boards damaged.
EF1	Moderate Damage	86-110 mph 126-179 km/h	Roofs torn off frame houses; windows and glass doors broken; moving autos blown off roads; mobile homes demolished; boxcars overturned.
EF2	Considerable Damage	111-135 mph 180-227 km/h	Roofs torn off well-constructed houses; foundations of frame homes shifted; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground.
EF3	Severe Damage	136-165 mph 228-308 km/h	Some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted; heavy cars lifted off the ground and thrown; structures with weak foundations blown away some distance.
EF4	Devastating Damage	166-200 mph 309-324km/h	Well-constructed houses and whole frame houses completely leveled; structures with weak foundations blown away some distance; trees debarked; cars thrown and small missiles generated.
EF5	Incredible Damage	> 200 mph > 324km/h	Strong frame houses leveled off foundations and swept away; with strongest winds, brick houses completely wiped off foundations; automobile-sized missiles fly through the air in excess of 100 m (109 yd); cars thrown and large missiles generated; incredible phenomena will occur.