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Hurricane Stuff
Questions Pondered |
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Most of this information is compiled from www.weather.com and other sources.
I put this page together b/c during alot of conversations you always wonder
how and why things are.
Links
http://www.weather.com/encyclopedia/tropical/ -
all kinda tidbits, but its tangled
http://www.ares.org/weather/hurricane.htm
http://www.nhc.noaa.gov/
http://www.fema.gov/kids/hunames.htm -
information for kids
http://www.mthurricane.com/Information.htm -
lots of tables
http://www.gri.msstate.edu/eid/nd_hurrbook.php -
lots of info
-
Key things -
- Definition - A hurricane --- a Caribbean Indian word for "evil
spirit and big wind" --- is a large rotating system of oceanic tropical
origin with sustained surface winds of at least 74 mph somewhere in the
storm. Due to the earth's rotation, these storms spin counterclockwise in
the Northern Hemisphere, and clockwise in the Southern Hemisphere; both
types of hemispheric spins are referred to as cyclonic rotation.
- each "depression/disturbance" is given a number, once it hits wind
speeds of 39mph its given a name and a "storm" status, once it hits 74mph it
is given a "category" status
- Categories (more detail below)
|
Category |
1 -- Minimal |
2 -- Moderate |
3 -- Extensive |
4 -- Extreme |
5 --
Catastrophic |
|
Winds |
74 to 95 mph or 64 to 83
kts |
96 to 110 mph or 65 to 96
kts |
111 to 130 mph or 97 to 113
kts |
131 to 155 mph or 114 to 135
kts |
greater than 155 mph or 135
kts |
- names are a list of 23 names (male-female-male...) going through A-W. If
goes past W, then they are given Greek alphabet names: Alpha, Beta, Gamma,
Delta...etc. more info below
- 6 name lists are pretermined (6 year cycle)
- A name is retired and replaced with another based on: loss of life
(deaths) or monetary damage (any country can petition the WMO for retirement
of a name). Retired names can be reused after 10 years or retired
permanently.
- a storm is given a new name if crosses from Alantic to Pacific
- 1 knot = 1.15mph
- millibar - a metric measure of pressure. Atmospheric pressure is the
weight of a column of air on a given area of earth, typically one meter
squared or one centimeter squared (the most frequent unit of measurement is
the millibar, or mb). Troughs fall in four general categories: equatorial
troughs, monsoon troughs, frontal troughs, and surface troughs. Less is bad.
- Season (some can come earlier or later, but most fall in these
timeframes)
- Atlantic hurricane season starts June 1st and ends November 30th
- North Pacific the official season begins May 15th and ends November
30th
- Hurricane / Typhoon: A tropical cyclone in which the maximum sustained
surface wind (using the U.S. 1-minute average) is 64 kts (74 mph or 119
km/hr) or more. The term hurricane is used for Northern Hemisphere tropical
cyclones east of the International Dateline to the Greenwich Meridian. The
term typhoon is used for Pacific tropical cyclones north of the Equator west
of the International Dateline.
-
Hurricane Names
What's in a name? Naming of tropical storms and hurricanes has been going
on for centuries. Hurricanes that swept through the Caribbean were often named
for the saint's day on which they occurred.
Once a tropical disturbance intensifies to tropical storm
strength, with wind speeds above 39 miles per hour, the National Hurricane
Center (NHC) gives the tropical cyclone a name.
Prior to 1950, military weather forecasters assigned a number,
not a name, to tropical storms. For example, the
fifth tropical cyclone of the 1932 hurricane season was called "Hurricane
Number 5". For a short time, the military phonetic alphabet, such as Able,
Baker, and Charlie was used to assign names.
Beginning in 1953, tropical storms were assigned female names.
Names were listed in alphabetical order, with the first tropical storm of the
year given a name beginning with "A."
In 1978, both men's and women's names were included in the
eastern North Pacific storm lists. In 1979, the list of names was expanded to
include both male and female names in the Atlantic Basin.
Member nations of The World Meteorological Organization have
since revised the list to include names common to English, Spanish, and French
speaking peoples. The order of men and women alternates every year. For
example, in 1995 the list began with Allison. In 1996, it began with Arthur.
There are six lists of tropical cyclone names, each composed
of 23 names from A to W. The lists are used on a rotating basis. For
instance, the 1997 set will be used again to name storms in the year 2003.
If a tropical storm forms in the Atlantic and crosses over to
the Pacific, it will be given a new name.
Occasionally, a name is retired from the list when a
particular tropical cyclone has caused many deaths or a tremendous amount of
damage. Some retired names include Andrew, Bob, Camille, David, Elena,
Frederic, Opal, Fran, and Hugo.
Check out the names for this Hurricane Season in the Atlantic Basin and the Pacific Basin.
Check out further information on the hurricane season.
Whats Category >> The
Saffir-Simpson Damage-Potential Scale
This scale
was developed in the early 1970s by Herbert Saffir, a consulting engineer in
Coral Gables, Florida, and Dr. Robert Simpson, then Director of the National
Hurricane Center. The scale is based primarily on wind speeds and includes
estimates of barometric pressure and storm surge associated with each of the
five categories.
-
|
Category |
Central Pressure |
Winds |
Surge |
|
1
-- Minimal |
greater
than 980 mb or 28.94 in |
74 to 95
mph or 64 to 83 kts |
4 to 5
feet |
|
2
-- Moderate |
965 to
979 mb or 28.50 to 28.91 in |
96 to 110
mph or 65 to 96 kts |
6 to 8
feet |
|
3
-- Extensive |
945 to
964 mb or 27.91 to 28.47 in |
111 to
130 mph or 97 to 113 kts |
9 to 12
feet |
|
4
-- Extreme |
920 to
944 mb or 27.17 to 27.88 in |
131 to
155 mph or 114 to 135 kts |
13 to 18
feet |
|
5
-- Catastrophic |
less than
920 mb or 27.17 in |
greater
than 155 mph or 135 kts |
greater
than 18 feet |
- Category 1 [Minimal]
74 to 95 mph
- damage primarily restricted to shrubbery, trees, and unanchored
mobile homes; no substantial damage to other structures; some damage to
poorly constructed signs
- low lying roads inundated; minor damage to piers; small craft in
exposed anchorages torn from moorings
- Category 2 [Moderate]
96 to 110
mph
- considerable damage to shrubbery and tree foliage, some trees blown
down; major damage to exposed mobile homes; extensive damage to poorly
constructed signs and some damage to windows, doors and roofing
materials of buildings, but no major destruction to buildings
- coastal roads and low lying escape routes inland cut off by rising
water about 2 to 4 hours before landfall; considerable damage to piers
and marinas flooded; small craft in protected anchorage torn from
moorings
- evacuation of some shoreline residences and low lying areas
required
- Category 3 [Extensive]
111 to 130 mph
- foliage torn from trees; large trees blown down; poorly constructed
signs blown down; some damage to roofing, windows, and doors; some
structural damage to small buildings; mobile homes destroyed.
- serious flooding along the coast; many small structures near the
coast destroyed; larger coastal structures damaged by battering waves
and floating debris
- low lying escape routes inland cut off by rising water about 3 to 5
hours before landfall; flat terrain 5 feet or less above sea level
flooded up to 8 or more miles inland
- evacuation of low lying residences within several blocks of
shoreline may be required
- Category 4 [Extreme]
131 to 155
- shrubs, trees, and all signs blown down; extensive damage to roofs,
windows, and doors, with complete failure of roofs on many smaller
residences; mobile homes demolished
- flat terrain 10 feet or less above sea level flooded inland as far
as 6 miles; flooding and battering by waves and floating debris cause
major damage to lower floors of structures near the shore; low lying
escape routes inland cut off by rising water about 3 to 5 hours before
landfall; major erosion of beaches
- massive evacuation of all residences within 500 yards of the shore
may be required, as well as of single story residences in low ground
with 2 miles of the shore
- Category 5
[Catastrophic] greater than 155
mph
- trees, shrub, and all signs blown down; considerable damage to roofs
of buildings, with very severe and extensive damage to winds and doors;
complete failure on many roofs of residences and industrial buildings;
extensive shattering of glass in windows and doors; complete buildings
destroyed; small building overturned or blown away; mobile homes
demolished
- major damage to lower floors of all structures less than 15 feet
above sea level within 1500 feet of the shore
- low lying escape routes inland cut off by rising water about 3 to 5
hours before landfall; major erosion of beaches
massive evacuation of residential areas on low
ground within 5 to 10 miles of the shore may be required
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