Nature'sGiganticSnowPlough
OnJanuary 10, 1962, anenormouspieceofglacierbrokeawayandtumbleddownthesideofamountaininPeru. Ameresevenminuteslater, whencascadingicefinallycametoastoptenmilesdownthemountain, ithadtakenthelivesof 4,000 people.
Thisdisasterisoneofthemost “devastating”examplesofaverycommonevent: anavalancheofsnoworice. Becauseitisextremelycoldatveryhighaltitudes, snowrarelymelts. Itjustkeepspilinguphigherandhigher. Glaciersareeventuallycreatedwhentheweightofthesnowissogreatthatthelowerlayersarepressedintosolidice. Butmostavalanchesoccurlongbeforethishappens. Assnowaccumulatesonasteepslope, itreachesacriticalpointatwhichtheslightestvibrationwillsenditslidingintothevalleybelow.
Evenanavalancheoflightpowercanbedangerous, butthePeruviancatastrophewasparticularlyterriblebecauseitwascausedbyaheavylayerofice. Itisestimatedthattheicethatbrokeoffweighedthreemilliontons. Asitcrasheddownthesteepmountainsidelikeagiganticsnowplough, itsweptuptrees, bouldersandtonsoftopsoil, andcompletelycrushedanddestroyedthesixvillagesthatlayinitspath.
Atpresentthereisnowaytopredictoravoidsuchenormousavalanches, but, luckily, theyareveryrare. Scientistsareconstantlystudyingthesmaller, morecommonavalanches, totrytounderstandwhatcausesthem. Inthefuture, perhapsdangerousmassesofsnowandicecanbefoundandremovedbeforetheytakehumanlives.?
1. Thefirstparagraphcatchesthereader'sattentionwitha ?_____?.
A. firsthandreport?
B. dramaticdescription?
C. talltale?
D. vividworldpicture ?
2. Inthispassage "devastating" means ?______?.
A. violentlyruinous?
B. spectacularlyinteresting?
C. stunning?
D. unpleasant ?
3. Thepassageismostlyabout ?______?.?
A. avalanches
B. glaciers
C. Peru
D. mountains