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<br />KI! 1110-2-1106
<br />5 Jan 60
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<br />CIUPTER 8
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<br />\JU:\L :-':\OW On-ER
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<br />8 01. DEF[N"IT!O~IS. Tbt' ternl ,i.,'/(I)il' Cul'(r l'd'n..; to the C'xtL'llt of U1C ground arca covered by
<br />SLOW, l't'~,-tldl('~~ of tIll' depth of SIlOW or its \\':llcr eqlJiyalrllL \\'bil(1 tbe j(lrm 81/liu'j)([ck refers to the
<br />toLd yolull (~of SIlll\\' (jtl <.1 l)~t..;ill. .....:..ll(J',\--('()\-PI ({(('f( (;(;/! is j be inCl"Ctl-":I' in snow con>r, ilnd SllO\\'-Con'f
<br />(/{plctiull refers to L dCCH\;\SC ill snOW-l'O\~U'('(; arC;l. ~-l('c/ln'1JI(lf;f)TI. of tIll.' :;llowpuck is Ih(' Hl't incrcrsc
<br />in hasin snowrack '\\','.tPf f'q111ndi'J1t. (u::wdl~- ('X!H'(-'s:;.cd in inches), w]lile ablation refers to a net
<br />volumetric dCCI'C,l':e of the sl1o'spa'.k \Ya:rr ('lllli,',tlerlt..
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<br />8-02. USE OF S.'I'OW.COYEH DATA. TIle priIlCip<lllh" of ,nO\H'OWr data is for oLt<lining the
<br />areal exti'nt of slj(,\\rw.lt at:l ;:i\'('n lime, fl)l' till' p)lrpll~:l' uf hydrogmph synthesis, Thi:3 ma)~ be
<br />iJlyolvrd in cstnbli,;;hnf.! procedure::; f()l' streamflow r('(,oll~-lit lltions~ short~t('rIll forecasts, or cksipl-
<br />flood ('ornn,!tlltiol1~~, The s('('olld ll,,(' of SIlO'.Y--('(I\'('r dU!:I :,.; ill connectioll with yolurnctric forec,lsts
<br />of 8eilscul rtlllofr. \\ hii'll is nutsi,Je of thr. S('O!W of j hi::. IlI:Ulual. E,",duntion of SIlOW-CO\Ver is
<br />extrClIldy importa ,It in hydrn;::T:lph S,\ ntl ('~i:;;;; ~~d, b{'(';lllSl' uf difficulties ill ohtailiillg dirpct ohsi'n'a-
<br />til !IS of ~llm,"-coyC't'l'd :.\ I'e:l , 11 i" 11S,l1l11~- eslilllated indin)dl~~. :-;'ll('h t'~til1l<ltf's lllny he COTlsidcrilbly
<br />:11 {'lTor, und in thr.' oY('rall S!lOWTlll)lt rU!lo1T d"h'rmilJati'Jll, Ill(' S!l()W-cOYl>l"cd area lllilY be kno\yn
<br />l('~.;s pr('cisely than s u\\'Inrlt or r:lIIoft' L1ct()r~.
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<br />8-03. S~OW.COYER I~FOR:\JATIOX. Dirc,.( o\l;'.n,ttioll of SilO'" conr can bl' accomplished
<br />b.\~ diref't n'collllal~~fLlll'(' or phutogrnphy, eitlH'r fj'('11l the air or fl'OJll thl' S!"l'Oulld. SO!llr ohservaticIlS
<br />are of the t~~pe tllat are lilllit()d to re.-=.tri('trr! pnrtionsof tlll' basin and tl1en)by seryc as indexes of
<br />SIlOW rov!'r. Other:; llfl' (,s::;;i'lltinll~~ COlllplde :.Illd SenT a~ a tnH' clt'll'l'lllinatioll of snow cover.
<br />r>qH'riellCe has showll that tlh' 1110:'1. rr>lialJlP and t'COIHlllli\'ul lllethod of ohtttiIlillg thp ilctual snOlY-
<br />covered tH'('tl i:-; al'l'id r(,(,oflIlai:;~an '\..). In H p~lrti('ld:lr yc,lr, :-:p\.eml such observations are rrquirrd
<br />during tlie -.;IlOl\~-COVrr ih'pletj')!l pl'riod. and "SIlOW 1'0\'('1' vcr-.;tls runoff" {'Ul'Y(,S call be constructed
<br />which sprv,' as n '6fl~,i3 for drtCl'lllining snow COY('I' contillllollSI:" during 111(' llldt s('ason, After
<br />snow co,"()r 111.1S heen observed ~ystcrl1aticl.dly for ,l prriod of )"I'aI'5. it is pll:"sil.>le empirically to relate
<br />snow-con'I' dt'pl('l ion to allY of ~e\"(,l'<Ll para'l]('ti'l':-:~ sl!rb :1:-:: \\"alel' eC}lIivall'llt OIl snow courses, date
<br />of disappearallce of Sllm\~ ilL sl'L'd,'d lllrtenrnlogical st:ltions, grcl1.i!ld pbotograDhs of srlectrd
<br />mount'1111 areas, :H'CIIlllubt('d rUllofl', or n)IIlUillil1g: rllllO:!'.
<br />III IllOll11tai!l()llS rq..:ions. sm>,,,]iJ'l' illforlllatinn, in conjullction \\illt ftl'ea-dcvation data,
<br />provid(.c; an illllqWlldi,tlt method f\)l" (>\~(lLlt'_tillg snow con'!'. .\lso, snl)\\~ course \\'titer equivaknt
<br />mr,lsurcI\1enjs ]]],1,\' l)(~ Ilsrd :IS t1 ~\lid(' in d\,tl'l'Inin:-ltiOfl of the snowliTlr~ by plotting the wa-:er
<br />('qlli\~ah'nt of indi\"iclual SIlO\," ('0111'>(':;;; \\'itIJin ;1 ba::-.ill nr surroulldilli! areas, as a function of devalion.
<br />_A n'gre;.;:-;io~l lilll~ dnl\\ 11 through pi Jttl'd T)di 'lt~ lll:ty Ll' Ibl.d to ddl)rmilll' the snmdil]e by its inL'r-
<br />sl.ctiOTl \\-ith zero '\Y It'\r eqlliY,dr!:!_ ordinate, Il\:\sllllleh :i.':; snow C(JtJl''3f'S :Ire genrt'nlly locatC'd in
<br />arras of ,thO\'i~ Jlor llnl snO\\~ :lCclltnllbtion fnr n gi,"('lI \)I(",":Llion zone, the snowline determined from
<br />srO\\~ courses i~ u":;llally too 10\\' in rkn1l ion, and :lli t~rb__trl.u.'T 111m"anI adju:,;tment of the snowline
<br />estin1<ltn ShOllld 1)(' ll1ad(l,
<br />Djl';'I,t l'vnluatioll nf ,';110\\" CO\'(')' 1).\~ aedal plint(';-.:mphy is liot practical for operational use in
<br />proj\..~ct bn~inc:;. lwcHIlSe of time, w(':\ll!pr, find eco!lomic considf'fntiolls. A(.rial photos may be
<br />useful, l!O\\'(_)n'l', ,h ill' kxC'<.:. nf SilO\\' con)l', or for l1:,e in hasic stuclirs 'whrre time of processing and
<br />nnalyzing thl'lll j~ tllt criticill
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