GLOFs from moraine-dammed lakes: their causes and mechanisms V. Vilímek, A. Emmer

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1 GLOFs from moraine-dammed lakes: their causes and mechanisms V. Vilímek, A. Emmer Department of Physical Geography and Geoecology, Faculty of Science, Charles University, Prague, Czech Republic

2 Presentation structure I. GLOFs (introduction) II. Causes of GLOFs from moraine-dammed lakes - dam destruction x dam overflow - dynamic causes - long-term causes III. GLOFs in different regions - causes representation, time distribution with examples from Cordillera Blanca, Peru

I. Glacial lake outburst floods (GLOFs) Sudden water release from glacial lake (moraine-dammed, ice-dammed or bedrock) Peak discharge, high erosion and transport potential => catastrophic impacts

3 I. Glacial lake outburst floods (GLOFs) Sudden water release from glacial lake (moraine-dammed, ice-dammed or bedrock) Peak discharge, high erosion and transport potential => catastrophic impacts Relation to various types of natural hazards (dynamic slope movements, earthquakes, extreme rainfalls) file:///c:/users/adam/desktop/škola/projekty/auc/nhess/figures/figure%203.jpg Huaraz, Peru, after outburst of Palcacocha Lake

4 II. Dam destruction x dam overflow Depends on the type of the dam (moraine x bedrocks) Morphometric parameters Etc. Palcacocha lake

5 The dam destruction (Palcacocha Lake, 1941) Before and after the outburst Significant sediment contribution through landslides, erosion etc. Damage

6 Lake ARTIZON BAJO, February 8th, m 2011 The lake volume before the event (254,136 m 3 ) and after (105,592 m 3 ) The probable cause: landslide into the lake

7 The dam overflow GLOF from Laguna 513 (under Hualcán Mt.)

possible landslide damming of the Chucchún River Photo of the bridge

centerline with cross sections (the blue lines show modeled water

8 Flood modelling - Hualcán Mt. Model of the bridge with destroyed deck in HEC-RAS Cross section with possible landslide damming of the Chucchún River Photo of the bridge with deck destroyed during the flood event Plan view of the river centerline with cross sections (the blue lines show modeled water surface extents during the peak discharge) Flood lines enable identification of safe and endangered areas along the stream

9 Dam destruction

10 Dynamic causes of GLOFs Slope movement into the lake Earthquake Intensive rainfall / snowmelt Flood wave form lake situated upstream Blocking of underground outflow cannals

11 Slope movements into the lake Various types of dynamic slope movements (rock falls, landslides, ice falls, snow avalanches) into the lake lead to surge (displacement) wave, which may overflow or erode and thus destruct moraine dams

12 Ice falls Due to glacier retreat lake Palcacocha grows significantly

13 Only for illustration

14 Earthquake Large earthquake may initiate changes in internal structure of moraine dam and thus cause dam rupture or internal erosion (piping) Also slope movements may be initiated by an earthquake Conversely earthquake may stabilize moraine dam

15 Flood wave from lake situated upstream

16 Flood wave endangered the lake situated downstream

17 Long-term causes Buried ice melting Hydrostatic pressure impact Time effect (dam degradation) dam selfdestruction = combination of longterm causes, without any evident dynamic cause

18 III. Regional specifics of GLOFs In different regions, various causes are significant (based on our GLOFs database)

19 Time distribution is also regionally specific

20 @ North America rather well distributed through time Cordilera Blanca after 1970 there has been done a lot of work to improve safety Central Asia older events may not be known

GLOFs database Under construction Based on research into scientific literature and unpublished reports (ANA office, Huaraz, Peru) Events from all over the world opportunity for international

21 GLOFs database Under construction Based on research into scientific literature and unpublished reports (ANA office, Huaraz, Peru) Events from all over the world opportunity for international cooperation Application for ICL Project this year (ICL = International Consortium on Landslides) More than one hundred events from across the globe currently online (

22 GLOFs database AIM: complete database with comprehensive information: lake type, probable cause of GLOF, flood volume, impacts (social and geomorphic), PURPOSE: Identification of regional differencies (specifics) of GLOFs => important step for creating optimal regionalfocused method of hazard assessment If any questions or comments, please use or author

23 Recent work - future aims Develop and fill GLOFs database Identification of regional-specifics Based on these data, create a new regionally-specific method of GLOF hazard assessment for Cordillera Blanca

24 Conclusions 1) GLOFs represent significant threat for inhabitants of high-mountain areas in these days of global climate change and glacial retreat 2) There are five dynamic and three long-term causes of moraine dam destruction with close relation to various types of natural hazards 3) The most frequent cause of GLOFs from morainedammed lakes is ice-fall into the lake, producing surge wave; other causes were registered with varied frequency

25 REFERENCES Clauge, J.J. and Evans, S.G.: A review of catastrophic drainage of moraine-dammed lakes in British Columbia, Quaternary Science Reviews, 19, , Costa, J.E. and Schuster, R.L.: The formation and failure of natural dams, Geological Society of America Bulletin, 100, , Emmer, A.: Analysis of moraine-dammed lakes destructions (bachelor thesis, leadership by V.Vilímek, in czech), 82 pp, Grabs, W.E. and Hanisch, J.: Objectives and prevention methods for glacier lake outburst floods (GLOFs), in: Snow and Glacier Hydrology (Proceedings of the Kathmandu Symposium, November 1992), Great Yarmouth (UK), , Ives, J.D., Shrestha, B.R., Mool, P.K.: Formation of Glacial Lakes in the Hindu Kush-Himalayas and GLOF Risk Assessment, International Centre for Integrated Mountain Development (ICIMOD), Kathmandu (Nepal), 56 pp., Lliboutry, L., Morales, B.A., Pautre, A., Schneider, B.: Glaciological problems set by the control of dangerous lakes in Cordillera Blanca, Peru. I. Historical failures of moranic dams, their causes and prevention, Journal of Glaciology, 18 (79), , McKillop, R.J. and Clauge, J.J.: Statistical, remote sensing-based approach for estimating the probability of catastrophic drainage from moraine-dammed lakes in southwestern British Columbia, Global and Planetary Change, 56, , 2007a. O'Connor, J.E., Hardison, J.H., Costa, J.E. (eds.): Debris flows from failures of Neoglacial-age moraine dams in the Three Sisters and Mount Jefferson Wilderness areas, Oregon, U.S. Geological Survey, Reston (Virginia), 93 pp., Richardson, S.D. and Reynolds, J.M.: An overview of glacial hazards in the Himalayas, Quaternary International, 65/66, 31-47, Vilímek, V., Zapata, M.T., Klimeš, J., Patzelt, Z., Santillán, N.: Influence of glacial retreat on natural hazards of the Palcacocha Lake area, Peru, Landslides, 2, , Yamada, T.: Glacier Lake and its Outburst Flood in the Nepal Himalaya, Japanese Society of Snow and Ice, Tokyo, 96 pp., 1998.

26 THANK YOU FOR YOUR ATTENTION

The Potentially Dangerous Glacial Lakes

Chapter 11 The Potentially Dangerous Glacial Lakes On the basis of actively retreating glaciers and other criteria, the potentially dangerous glacial lakes were identified using the spatial and attribute