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1、◎AvalancheandItsSafetyAnavalancheisasuddenandrapidflowofsnow,oftenmixedwithairandwater,downamountainside.Avalanchesareamongthebiggestdangersinthemountainsforbothlifeandproperty.Allavalanchesarecausedbyanover-burdenofmaterial,typicallysnowpack,thatistoomassiveandu
2、nstablefortheslopethatsupportsit.Determiningthecriticalload,theamountofover-burdenwhichislikelyanavalanche,isacomplextaskinvolvingtheevaluationofanumberoffactors.Terrainslopesflatterthan25degreesorsteeperthan60degreestypicallyhavealowriskofavalanche.Snowdoesnotga
3、thersignificantlyonsteepslopes;also,snowdoesnotfloweasilyonfiatslopes.Human-triggeredavalancheshavethegreatestincidencewhenthesnow'sangleofrest1isbetween35and45degrees;thecriticalangle,theangleatwhichthehumanincidenceofavalanchesisgreatest,is38degrees.Theruleofth
4、umb2is:Aslopethatisflatenoughtoholdsnowbutsteepenoughtoskihasthepotentialtogenerateanavalanche,regardlessoftheangle.Additionally3,avalancheriskincreaseswithuse;thatis,themoreaslopeisdisturbedbyskiers,themorelikelyitisthatanavalanchewilloccur.Duetothecomplexityoft
5、hesubject,wintertravellinginthebackcountry4isnever100%safe.Goodavalanchesafetyisacontinuousprocess,includingrouteselectionandexaminationtothesnowpack,weatherconditions,andhumanfactors.Severalwell-knowngoodhabitscanalsoreducetherisk.Iflocalauthoritiesissueavalanch
6、eriskreports,theyshouldbeconsideredandallwarningsshouldbepaidattentionto.Neverfollowinthetracksofotherswithoutyourownevaluations;snowconditionsarealmostcertaintohavechangedsincetheyweremade.Observetheterrainandnoteobviousavalanchepathswhereplantsaremoiisingordama
7、ged.Avoidtravelingbelowotherswhomighttriggeranavalanche.◎GiantStructuresItisanimpossibletasktoselectthemostamazingwondersofthemodemworldsinceeveryyearmore__wonderful_ constructionsappear.Herearethreegiantstructureswhichareworthyofour __admiration__ althoughtheyma
8、yhavebeensurpassedbysomemorerecentwonders.ThePetronasTwinTowersThePetronasTowerswerethetallestbuildingsintheworldwhentheywerecompletedin1999.Witha__height_ of4
