Himalayan Geology, Vol. 38 (1), 2017, pp. 12-29, Printed in India 12 Sedimentary and Geomorphic Signatures of a Cloud burst and triggered flash floods in the Indus valley of Ladakh Himalaya S.J. SANGODE , D.C. MESHRAM , S. RAWAT ,Y. KULKARNI , D.M. CHATE , S.S.GUDADHE 1 1 2 3 4 1 1 2 3 4 Department of Geology, Savitribai Phule Pune University, Pune-411007, India Wadia Institute of Himalayan Geology, Dehradun-248001, India Gharda Institute of Technology, Lavel, Khed, Ratnagiri-415708, India Indian Institute of Tropical Meteorology (IITM), Pune-411007, India Abstract: Keywords Post-facto documentation is made to record the signatures of a major cloud burst and triggered flash floods in the Leh Valley region of the Indus River (Ladakh Himalaya) occurred during 2010. The most notable signatures include linear imbricate alignment of the sub-rounded boulders, paired bank-erosion, sharp axial incision of the stream beds and overbank debris flow-sheet flood deposits. After a detailed tape-, compass- and GPS based mapping of total 11 affected streams from the cloud burst-hit Ladakh batholithic range, a three stage model has been suggested. Stage I involved rapid initial recharge of the streams and gullies with high volume of entrapped Quaternary sediments generating the granular flow under accelerated gravitational thrust. Stage I also resulted in the significant bank erosion in the middle- and lower reaches. Stage II was marked by hyper-concentrated flow that produced sheet flood deposits over the valley floor. Stage III recorded terminal phase with sediment poor discharge that prolonged with the rains past the main event. Rapid recharge and discharge from extremely narrow, high gradient transverse streams and gullies, high volume of entrapped Quaternary sediment mass, combined with a proportionately large de-glaciated catchment yielded the catastrophic mass transfer downstream. The affected streams appear to have produced several pulses of sedimentation of large variation in sediment texture and flow viscosity within a short duration. These conditions demand more detailed studies to describe the cloud burst triggered flash flood deposits within the classical approaches of debris flow mechanism in the Himalayan setup. Detailed mapping and estimation of the entrapped sediment mass within the transverse stream valleys of various sectors of Himalaya is required to predict the style of mass transfer during such events. Our study observed that the present cloud burst have released only a small volume of the entrapped mass offsetting the stage for additional mass transfer during similar future events in the region. : Ladakh Himalaya, Indus valley, Flash flood, Cloud burst. yn~nk[k fgeky; dh fla/kq ?kkVh esa es?k foLQksV rFkk ifj.kkeh vkdfLed iwj ds volknh rFkk Hkwvkd`frd izek.k ,l-ts- lkaxksM+s ] Mh-lh- esJke ] ,l -jkor ] okb- dqyd.khZ ] Mh-,e- pkVs ] ,l-,l- xqMk/ks 1 1 2 3 4 1 1 2 4 HkwfoKku foHkkx] lkfo=hckbZ Qqys iq.ks fo|kihB] iq.ks 411007 Hkkjr okfM;k fgeky; HkwfoKku laLFkku] 33 tujy egknso flag jksM] nsgjknwu Hkkjr bafM;u baLVhV;wV vkWQ VªkWfidy fefV;ksjksykWth ¼vkb vkb Vh ,e½] iq.ks 411007 Hkkjr & ] ] & ] ~ & ] & fgeky;½ 248001 ?kjnk baLVhV;wV vkWQ VsDukWykWth] ykosy] [ksM] jRukfxjh 415708 Hkkjr 3 lkjka'k fla/kq unh ds ysg ?kkVh Hkkx ¼yn~nk[k esa lu~ 2010 esa gq, izeq[k es?k foLQksV rFkk ifj.kkeLo:i vk;s vkdfLed iwj dk ?kVuk mijkUr izys[ku fd;k x;kA mixksfyr xksyk'eksa dk jSf[kd dksjNknh ljs[k.k] ;qXe rV vijnu] izokg ry dk v{kh; dVko rFkk rVksifj eyok izokg & ijr ck<+ fu{ksi eq[; izek.k gSaA yn~nk[k egkLdU/k Js.kh ds es?k foLQksV ls izHkkfor 11 ty izokgksa dk Qhrk] fnDlwpd rFkk th ih ,l }kjk foLr`r ekufp=.k djds bl fØ;kfof/k dh O;k[;k djus ds fy;s ,d f=Lrjh; ekWMy izLrkfor fd;k x;k gSA igys Lrj ij lfjrkvksa rFkk voukfydkvksa ds izkjfEHkd 'kh?kz iquHkZj.k ls fupys Hkkx esa c`gr~ DokVuZjh xksyk'eksa rFkk d.kksa dk c<+s xq:Rokd"kZ.k ds dkj.k izy;dkjh LFkkukUrj.k gqvk ftlls izokgksa ds e/;e rFkk fupys Hkkxksa esa dkQh vijnu gqvkA f}rh; Lrj ij ?kkVh ry esa vfr lkUnz cgko }kjk ck<+ pknj fu{ksi.k gqvkA r`rh; Lrj cgko dk vafre pj.k Fkk tc eq[; ?kVuk Øe ds ckn tkjh o"kkZ ds lkFk volkn&ty ds de vuqikr dks vafdr fd;k x;kA vR;Ur ladjh] vfr <ky okyh vuqizLFk lfjrkvksa rFkk voukfydkvksa ls rst iquHkZj.k rFkk foltZu] izkIr foikf'kr DokVuZjh volkn ek=k dh cgqyrk rFkk vis{kkd`r c`gr~ fofgeufnr tyxzg.k ds ifj.kkeLo:i fupys Hkkxksa esa izy;dkjh c`gr~ LFkkukUrj.k gqvkA ,slk yxrk gS fd izHkkfor lfjrkvksa us vYi dky esa xBu rFkk izokg ';kurk esa ifjorZu ds lkFk volknksa ds dbZ LiUnu %