Hurricane Hazards: Winds
Hurricane Winds
The
intensity of a landfalling hurricane is expressed in terms of
categories that relate wind speeds and potential damage. According to
the Saffir-Simpson Hurricane Scale,
a Category 1 hurricane has lighter winds compared to storms in higher
categories. A Category 4 hurricane would have winds between 131 and 155
mph and, on the average, would usually be expected to cause 100 times
the damage of the Category 1 storm. Depending on circumstances, less
intense storms may still be strong enough to produce damage,
particularly in areas that have not prepared in advance.
Tropical storm-force winds are dangerous to those caught in them.
For this reason, emergency managers plan on having their evacuations
complete and their personnel sheltered before the onset of tropical
storm winds, not hurricane-force winds.
Hurricane-force winds can easily destroy poorly constructed
buildings and mobile homes. Debris such as signs, roofing material, and
small items left outside become flying missiles in hurricanes.
Extensive damage to trees, towers, water and underground utility lines
(from uprooted trees), and fallen poles cause considerable disruption.
High-rise buildings are also vulnerable to hurricane-force winds,
particularly at the higher levels since wind speed tends to increase
with height. Recent research suggests you should stay below the tenth
floor, but still above any floors at risk for flooding. It is not
uncommon for high-rise buildings to suffer a great deal of damage due
to windows being blown out. Consequently, the areas around these
buildings can be very dangerous.
The strongest winds usually occur in the right side of the eyewall
of the hurricane. Wind speed usually decreases significantly within 12
hours after landfall. Nonetheless, winds can stay above hurricane
strength well inland. Hurricane Hugo (1989), for example, battered
Charlotte, North Carolina (which is 175 miles inland) with wind gusts
to nearly 100 mph.
