|
 | ||
       | |||
 |
|
In the 1970s, NOAA (the National Oceanic and Atmospheric
Administration) developed a disaster potential scale to aid forecasters in
predicting the destructive power of a hurricane called the Saffir-Simpson
Hurricane Scale. According to the book Hurricane Watch by Bob Sheets and Jack
Williams, the original
categorical measurement levels were developed in 1971 by structural engineer
Herbert Saffir as part of his work with the United Nations to assess the
potential for wind damage to low cost housing. The following year, Saffir’s
original work was expanded upon by Robert Simpson (then director of
In
1972, the Saffir-Simpson Hurricane Scale debuted (see Reference #1); it is
only used to classify storms in the Atlantic Basin and northern Pacific Ocean
east of the International Date Line (in other words, it is not used to classify
typhoons and cyclones). Before Saffir and Simpson categorized hurricanes, they
were known as either “major or minor” – after the implementation of the scale,
the
At the beginning of the 2009
Storm surge is just as dangerous (and sometimes
even more) than wind damage and somewhat unpredictable under the old
Saffir-Simpson model. In 2008, an unexpected storm surge of 13 to 18 feet
(usually associated with a Category 4 storm) accompanied Hurricane Ike (a
Category 2 storm) when it made landfall in
In taking action on a new scale, the NHC addressed
concerns about non-evacuations by complacent residents ignoring storm surge
warnings of areas not in a direct path of a storm, as well as any unnecessary
mass exodus clogging potential evacuation routes and putting a strain on
infrastructure. With the new separate scales (and better forecasting tools),
meteorologists would be able to emphasize potential wind and flood danger for different areas. Other changes to the revised
wind scale include a much more detailed prediction of damage, an associated
aftermath of a hurricane’s devastation (in the form of power outages) and a
grim no-nonsense assessment of the possibility of injury or death.
Here is the new Saffir-Simpson Hurricane Wind Scale
(Categories 1-5) along with “tropical” definitions. At the bottom of this page
is the old “pre-2009” Saffir-Simpson Hurricane Scale:
A moving area of thunder
storms in the Tropics that maintain its identity for 24 hours or more. As it
organizes, look for it to develop into a tropical depression.
An organized weather
system of clouds and thunderstorms. There is a defined circulation.
An organized weather
system of strong storms. Again, there is a defined circulation.
Damaging winds are
expected. Some damage to building structures could occur, primarily to
unanchored mobile homes (mainly pre-1994 construction). Some damage is likely
to poorly constructed signs. Loose outdoor items will become projectiles,
causing additional damage. Persons struck by windborne debris risk injury and
possible death. Numerous large branches of healthy trees will snap. Some trees
will be uprooted, especially where the ground is saturated. Many areas will
experience power outages with some downed power poles.
Very strong winds will
produce widespread damage. Some roofing material, door, and window damage of
buildings will occur. Considerable damage to mobile homes (mainly pre-1994
construction) and poorly constructed signs is likely. A number of glass windows
in high rise buildings will be dislodged and become airborne. Loose outdoor
items will become projectiles, causing additional damage. Persons struck by
windborne debris risk injury and possible death.. Numerous large branches will
break. Many trees will be uprooted or snapped. Extensive damage to power lines
and poles will likely result in widespread power outages that could last a few
to several days.
Dangerous winds will
cause extensive damage. Some structural damage to houses and buildings will
occur with a minor amount of wall failures. Mobile homes (mainly pre-1994
construction) and poorly constructed signs are destroyed. Many windows in high
rise buildings will be dislodged and become airborne. Persons struck by
windborne debris risk injury and possible death. Many trees will be snapped or
uprooted and block numerous roads. Near total power loss is expected with
outages that could last from several days to weeks.
Extremely dangerous winds
causing devastating damage are expected. Some wall failures with some complete
roof structure failures on houses will occur. All signs are blown down.
Complete destruction of mobile homes (primarily pre-1994 construction).
Extensive damage to doors and windows is likely. Numerous windows in high rise
buildings will be dislodged and become airborne. Windborne debris will cause
extensive damage and persons struck by the wind-blown debris will be injured or
killed. Most trees will be snapped or uprooted. Fallen trees could cut off
residential areas for days to weeks. Electricity will be unavailable for weeks
after the hurricane passes.
Catastrophic damage is
expected. Complete roof failure on many residences and industrial buildings
will occur. Some complete building failures with small buildings blown over or
away are likely. All signs blown down. Complete destruction of mobile homes (built
in any year). Severe and extensive window and door damage will occur. Nearly
all windows in high rise buildings will be dislodged and become airborne.
Severe injury or death is likely for persons struck by wind-blown debris.
Nearly all trees will be snapped or uprooted and power poles downed. Fallen
trees and power poles will isolate residential areas. Power outages will last
for weeks to possibly months.
Old Saffir-Simpson Hurricane Scale (pre
2009):
No real damage to
building structures. Damage primarily to unanchored mobile homes, shrubbery and
trees. Also, some coastal flooding and minor pier damage…
Some roofing material,
door and window damage to buildings. Considerable damage to vegetation, mobile
homes and piers. Coastal and low-lying escape routes flood 2-4 hours before
arrival of center. Small craft in unprotected anchorages break moorings. Storm
surge expected to be 6 to 8 feet…
Some structural damage to
small residences and utility buildings with a minor amount of curtain-wall
failures. Mobile homes are destroyed. Flooding near the coast destroys smaller
structures with larger structures damaged by floating debris. Terrain
continuously lower than five feet ASL (at sea level) may be flooded inland 8
miles or more. Storm surge expected to be nine to 12 feet…
More extensive
curtain-wall failures with some complete roof structure failure on small
residences. Major erosion of beach. Major damage to lower floors of structures
near the shore. Terrain continuously lower than ten feet
Complete roof failure on
many residences and industrial buildings. Some complete building failures with
small utility buildings blown over or away. Major damage to lower floors of all
structures located less than 15 feet
Reference #1: Sheets, Bob and Jack Williams. Hurricane
Watch. 1st.
Reference #2: In order (from 2004 to 2005), those seven
storms were
|
|
site created by JJ Paolino © 2008-2011 |