Back
to hurricane background and preparedness information
courtesy
of National
Hurricane Center
HIGH
WINDS
SAFFIR-SIMPSON
HURRICANE SCALE
HURRICANE
WIND DECAY
RISK
AREAS
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 strong enough to be 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-force 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.
|
Windows falling from a high-rise building
Burger
King Headquarters' CEO office
in Miami after Hurricane Andrew
Damage
from Hurricane Frederic (1979)
|
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.
As
indicated in the Basics section, the strongest
winds usually occur in the right side of the eyewall
of the hurricane. Wind
speed ususally 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
gusts to nearly 100 mph.
The INLAND HIGH WIND MODEL can be used by
emergency managers to estimate how far inland strong
winds extend. The inland
wind estimates can only be made shortly
before landfall when the windfield forecast errors
are relatively small. This information is most useful
in the decision-making process to decide which people
might be most vulnerable to high winds at inland
locations.
QUESTIONS
TO ASK YOUR COMMUNITY LEADERS
Does your community building code set standards
that will help buildings withstand winds in a major
hurricane?
Do
your shelter facilities include long-span roofs
or unreinforced masonry walls (such as gymnasiums)
that are vulnerable in high winds?
Before
A Hurricane Threatens
Find
out if your home meets current building code requirements
for high-winds. Experts agree that structures built
to meet or exceed current building code high-wind
provisions have a much better chance of surviving
violent windstorms.
MORE
INFO
Protect
all windows by installing commercial shutters or
preparing 5/8 inch plywood panels.
MORE
INFO
Garage
doors are frequently the first feature in a home
to fail. Reinforce all garage doors so that they
are able to withstand high winds.
MORE
INFO
If
you do not live in an evacuation zone or a mobile
home, designate an interior room with no windows
or external doors as a “Safe Room”.
MORE
INFO
Before
hurricane season, assess your property to ensure
that landscaping and trees do not become a wind
hazard.
-
Trim dead wood and weak / overhanging branches from
all trees.
-
Certain trees and bushes are vulnerable to high
winds and any dead tree near a home is a laydown
hazard.
-
Consider landscaping materials other than gravel/rock.
As
A Hurricane Approaches
No
mobile / manufactured home is safe in hurricane
force winds. Those residents should evacuate to
a safer structure once local officials issue a hurricane
evacuation order for their community.
Once
a hurricane warning is issued, install your window
shutters or plywood panels.
MORE
INFO
When
a hurricane warning is issued for your community,
secure or bring inside all lawn furniture and other
outside objects that could become a projectile in
high winds.
Listen
carefully for safety instructions from local officials,
and go to your designated “Safe Room”
when directed to do so.
Monitor
NOAA
Weather Radio.
Do
not leave your “Safe Room” until directed
to do so by local officials, even if it appears
that the winds calmed. Remember that there is little
to no wind in the eye of a hurricane.
