High Winds from Hurricanes
We continue our coverage of the 2014 Hurricane Preparedness Week by looking at two more of the hurricane hazards. In particular, we'll look at High Wind and Tornadoes.
Changes to NHC products for 2014 include Elimination of the Intensity Probability Table
Update on NHC Products and Services for 2014 (PDF)
- When associated with hurricanes, tornadoes are not usually accompanied by hail or a lot of lightning, clues that citizens in other parts of the country watch for.
- Tornado production can occur for days after landfall when the tropical cyclone remnants maintain an identifiable low pressure circulation.
- They can also develop at any time of the day or night during landfall. However, by 12 hours after landfall, tornadoes tend to occur mainly during daytime hours.
|F-Scale Number||Intensity Phrase||Wind Speed||Type of Damage Done|
|F0||Gale tornado||40-72 mph||Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.|
|F1||Moderate tornado||73-112 mph||The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.|
|F2||Significant tornado||113-157 mph||Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.|
|F3||Severe tornado||158-206 mph||Roof and some walls torn off well constructed houses; trains overturned; most trees in fores uprooted|
|F4||Devastating tornado||207-260 mph||Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.|
|F5||Incredible tornado||261-318 mph||Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-inforced concrete structures badly damaged.|
|F6||Inconceivable tornado||319-379 mph||These winds are very unlikely. The small area of damage they might produce would probably not be recognizable along with the mess produced by F4 and F5 wind that would surround the F6 winds. Missiles, such as cars and refrigerators would do serious secondary damage that could not be directly identified as F6 damage. If this level is ever achieved, evidence for it might only be found in some manner of ground swirl pattern, for it may never be identifiable through engineering studies|