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EncyclopedicEntry
rainshadow
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Arainshadowisapatchoflandthathasbeenforcedtobecomeadesertbecausemountainrangesblockedall
plant-growing,rainyweather.Ononesideofthemountain,wetweathersystemsdroprainandsnow.Ontheother
sideofthemountain—therainshadowside—allthatprecipitationisblocked.
Inarainshadow,it’swarmanddry.Ontheothersideofthemountain,it’swetandcool.Whyisthereadifference?
Whenanairmassmovesfromalowelevationtoahighelevation,itexpandsandcools.Thiscoolaircannothold
moistureaswellaswarmair.Coolairformsclouds,whichdroprainandsnow,asitrisesupamountain.Afterthe
airmasscrossesoverthepeakofthemountainandstartsdowntheotherside,theairwarmsupandtheclouds
dissipate.Thatmeansthereislessrainfall.
You’lloftenfindrainshadowsnexttosomeoftheworld’smostfamousmountainranges.DeathValley,adesertin
theU.S.statesofCaliforniaandNevada,issohotanddrybecauseitisintherainshadowoftheSierraNevada
mountainrange.TheTibetanPlateau,arainshadowinTibet,China,andIndiahastheenormousHimalaya
mountainrangetothankforitsdryclimate.
VOCABULARY
Term
PartofSpeech
Definition
airmass
noun
alargevolumeofairthatismostlyconsistent,horizontally,intemperatureand
humidity.
climate
noun
allweatherconditionsforagivenlocationoveraperiodoftime.
desert
noun
areaoflandthatreceivesnomorethan25centimeters(10inches)ofprecipitationa
year.
elevation
noun
heightaboveorbelowsealevel.
mountain
range
noun
seriesorchainofmountainsthatareclosetogether.
precipitation
noun
allformsinwhichwaterfallstoEarthfromtheatmosphere.
rainshadow
noun
drylandonthesideofamountainfacingawayfromprevailingwinds.
snow
noun
precipitationmadeoficecrystals.
weather
noun
stateoftheatmosphere,includingtemperature,atmosphericpressure,wind,humidity,
precipitation,andcloudiness.
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weather
system
noun
movementofwarmorcoldair.
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