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LESSoN2 INTRODUCING STORMS
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L[おSON 2 INTRODudING STORMS
involve rain and high winds.
Each usually occurs at certain
times of the year in certain
locations. They can be fore-
CaSt) detected, and tracked by
the National Weather Service.
丁h undeすsto事ms
A鳳understorm is a distur_
bance in the atmoaphere that
has so皿e or all of these: li如t-
ni鴫, thunder, guSty winds,
heavy rain, and hail. A severe
thunderstom can produce
hail the size of goIf ba11s,組ash
組oods, and even tomadoes.
Here are some key traits of
thunderstorms :
●血the southeastem Uhited
States, thunderstom鯵occur
皿ost o節en血ong血e G血f
Coast, eSPeCiany in Florida,
' Most thunderstorms occur
in血e spring and sumner
mon血s duri重喀血e warmest
Part Of the day. Althou釦-it
is rare, SOme thunderstorms
OCour duri鴫winteL Some
thunderstorms埼r ’examPle ,
in the Central Plains, OCCur
at night.
● A wdl-devefoped thmder-
storm can cover an area as
Ybu pIObab(y胎c喝)j始的ese cbuds
as拘undero/ouds, Or脚mu/on緬bus
cbuds. wh応h are o触n seen du噂
a thundeIStOrm.
STG′MSTM aATASTROPHIC EvENTS 21
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large as 8 to 16 square姐o-
● If the temperature in part of
a血undercIoud falls below
freezing and winds are stro鴫,
血e raindrops in血e s亡om
Can develop into hail.
● In a fraction ofa second, a
typical lightni垂bolt can dis_
Charge as much energy as a
mediun-Sized nuclear reac_
tor can in the same amourlt
of time.
' At any given moment, an
estimated 1500 to 2000
thunderstoms are occurring
On血e earth. These storms
ean tri幾er 6000 or more
嘩ht血鴫紐ashes per mimte.
漢bm adoes
How do tomadoes form? A tor_
nado is a rotati鴫col伽皿of air
血at foms from thunderstoms
OVer dry land under special
COndi也ons: When moisti相調
air: meetS COOI dry air head・On.,
Whats more, hurricanes o杜en
bring on tomadoes. Here are
SOme thi壇s you might like to
know about tomadoes:
● The Uhited States has more
tomadoes than any o血er
COuntry in the world. Most
tomadoes in Nbrth America
happen in ``Tbmado Auey.,,
This area is in the Central
h May 4999タ的isわmaめs汁uck
Ok居homa C働Ok佃homa.
22 STαMSTM cATASTROPHIQ EvENTS
之-瞥総主調.〇〇星雲一〇工◎
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〇日SSON 2 INTRODUCING STORMS
TypeofDamage 晦r高子・∴ �
言∴寧竣 �言で祉e七〇皿急do �65-116龍l°mete重S �Somechimneydamage.
perhour(車h)
�’冊eebranohesbrokenandshauowrootedtreespush紅dvei∴
(40-了2mi工es P9rhour[mph]) �Siさndamaさe.
’:’埠 �M6deratetomado �117-18工をph �Roofsurfa∞SPee置edo鮒 �� �
(73-112mph) �Mobi置ehomesovertumedorpushedo鮎foundation �
Movingautomobilespushedo鱈roads.
壇eessnapped.
Ⅵndowsbroken.
∴∴Fと �工signrfucanttomado �182-253車h �Ctonsideral)ledamage. �
�
(113-157皿ph) �Roo思tomoffframehouses,andmobilehomesdem
Railroadboxcarspushedover.
Largetreesuprooted.
Lighto埠iectsbecomemissiIes.
駒 ��Severetomado �254-332kph �Wallstomfro皿bu孤dings. � �
(工5&ゼ06皿ph) �Ga聯0Venumed.
Mosttreesi皿forestsuprooted.
∴:∴F4∴ ��Devasta債ngtomado �333一生19kh �WⅡ � � p (207-260mph)
�e-COnStruCtedhousesleveled.
Buildihgswithweakfoundationsblownsomedis
Cars.th重own.
Largeobjectsbecomemissiles.
F5 ��Incredib]etomado �420-513kph
�Automobile-SizedstructurescarriedmorethanlOOmeters_
(26l-318皿ph) �Barkstrippedfromtrees.
Steel-reinforoedconcretebuildingsba`uydamaged.
Plains between血e Rocky
Aめuntains and the
ississippi R王ve購
bout three-fourths of all
tornadoes in the United
States develop from March
to July, duri皿g late after-
noon" The month of May
normally has the greatest
number of tomadoes in
the United States (averag-
i鴫about five per day),
while the most vio工ent tor_
nadoes seem to occur in
April.
● The diameter of most toma_
does is between lOO and 600
m9ters, although some are
just a few meters wide, and
Others are wider than 1600
meters (1 mile).
' Some tomadoes stand nea轟y
Still, While others move at
SPeeds faster than lOO kiIo-
meters (62 miles) per hour,
● A tomadob vortex contains
SWirling w血ds that can
move up to 350 kilometers
(217 mifes) per hou意
. Viter坤outs are tomadoes
血at fbm over wa重賞
● Much of a亀mad疎des同工○○
tive power comes鮭om its
strong winds, iぬich o郷地
h鴫e o蹄ects and tum them
into dangerous,施gh-apeed
miss追es.
● Japanese心o皿meteo的logist
蹄健廿ya `く耽d網噂iね, W血o
WaS血0Wn aS `餌意的ma(め,,
developed the Ft癒ita scale
for measu血g tomadoes on
the basis of the damage they
CauSe (see the tal)le entitled“Fujita Scale of的madoes,,).
STC/MS耶 cÅTASTROPHIC EvEⅣTS 23
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i LESSoN2 INTRODUCING STORMS
嶋urricanes
What distingrlishes hurricanes
from thunderstorms and tor-
nadoes? One big di鮒erence is
that hurricanes are massive
rotating storrhs. And, they
always form wllen Warm,
moist air rises over tropical
waters. Here are some other
血ings you may want to血ow
about hurricanes:
・ People have di鱈erent na血es
for血ese rotating storms in
di鮪erent parts of the wodd.
For example, a rOtating
stom i; caued a hurricanewhen it forms north of the
equator in血e Atlantic and
eastem Pacific Oceans. It is
called a typhoon when it
24 STαMSTM cATASTROPHIC BvENTS
forms nor血of the equator
in the westem Paci鯖c Ocean.
It is called a cyelone when
it forms in the Indian Ocean
aI〕d off the coast of Australia.
. A hurricane is norma皿y 550
kilometers (342 miles) in
diameter It -rarely gets bi饗er
when it hits land, because it
gets most of its energy from
the warm ocean water
beneath it.
● Hurricanes can move at
speeds of 8 to 24 kilometers
(5 to 15 miles) per hour.
Sometimes they can become
neahy stationary・
・ Hurricanes begin as tropical
storms, Which have wind
speeds of 64 to l18 kilo-
meters (40 to 73 miles) per
in /afe summer 1985, Hur廟eane
E/ena affected mo憎的an l mi傭)n
peopIe励en /t moved from肋e創腔
of Mexico to Louis細na, Mississ毎pん
Afabama, and oen細I and northem
用o鵬.
hour. Hurricanes have wind
speeds of l19 to 250 kfro-
皿eters (74 to 155 miles) p農r
hour or more. (See the tal)l
entitled `` sa縦r/Simps on
Hurricane Scale.’’)
' Because hurricanes can las
a week or longer and sever
can occur at the same
time, naming them reduoe‘
confusion. (See血e table
entitled ``Selected Names
for Northem Hemisphere
Hur血CaneS.’’) □
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鵬SSON 2 INTRODUCING SでORMS
S重緬r/S盲mpson Hul.r雪cane Scaie
categb富y �W!ndSpeed �Damage �TybeofD鶴mage ���StormSurgeま
1 �119-153郎 �Mi鼠i血血 �Nosignificantdamagetobuildings.
���1-ゼ耽ete章s伍)
(7∠」95皿ph)
��Damageprimarilyto調aneho戴dmob孤ehomes,Shrubbery,andtrees.
���(4-5俺et[坤)
Somecoastal組oo(毘屯andm血OrPierdsmage.
2 �1き生-178kph �Moderate �Somedamagetoroo飼ng,doors,andwindows.
���2-2.5皿
(%-110皿p血) ��Considerabledamagetovegetationandmobilehomes.
���(己-8fe
剛oodingdamagetopiersandsma11craft.
3 �179葛210kph �Bx亡ensive
�So皿eStmCturaldamagetosma田residencesan意地ifty � � �∴2.7-3.7皿
(111-130叫丸) ��Mobilehomesdestroyed. ���’(9」2ゆ
FIoodingnearcoastdestroyssmallstructures;floatinま
damageslargerstructures.
hland組oodingpossible.
4 �211」250kph �Bxt重e皿e
�Completeroofstructurefailureonsmallhomes. � � �云 �百中
(131-155mph) ��Majorero§ionofbeaches. ���∴(1- �やめ
Inland組oodingpos§ible.
5 �250十最ph �Catastrophic
�Ctompleteroof鮎lureonmanyho皿eSandindrst轟albu址ings∴ ���:S詣 �坤
(15与十皿ph) ��Somebuildingscompletelydestroyed. �� �(事8十的・∴子
Smallutilitybuildingsblownoveroraway.
FIoodingoausesmajordamagetolowerfloorsofallstruotures.
near.shoreline.
Massiveevaeuatlonofpeoplepossible.
晒皿unusua11y high water level, Primar孤y due to winds during a
stom, eSPeCially a hurricane.
Selected Names fo寡Nol'them Hem冒spheがe H鵬細ricanes
(AtIantic OceanタG山f of Mex雪co, Ca曲bean Sea), lfear 2002細2OO5
200ま �2003 �2004 �2005
Arthur Lili �Ana La喜ry �Alex しisa �Arlene Lee
.Bertha Marco �B劃 M血dy �BoImie Matthew
�Bret M逼轟a
Cesar Nana �Claudette Nicholas �Chadey Nicole
�Ci鼠dy N祉e
Do皿y O調盆r �Damy Odette �Danielle Otto �De皿蕗 Ophe虹a
Edouard P狐o皿a �E轟k盆 Peter �Ea血 Paula
�Em組y Ph虹ippe
Fra皿 Rene �Fabian Rose �Frances Richard
�Fran最虹n Rita
Qustav Sa宣重y �Grace Sa皿 �Gasto皿 Shary �Ge虹 Stan
Hortense 購ddy �He皿富i 重もresa �Hermine Tb皿as
�HaⅣey 此慣1皿y
Isidore VIcky �Isabel Victor �Ivan VIrginie
�Irene Vince
Josephine W廿fred �.Juan Wanda �Jeanne Walter
�七〇se w址na
Kyle �Kate �駅a細 �重くat轟na一
NOTE Names were selected from library sources and agreed on at
meetings of the Wodd Meteorological Organization.
STC硯S刑【 cATASTROP櫨IC宙v聞TS 25
