Skip to main content

The 2020 glacial lake outburst flood process chain at Lake Salkantaycocha (Cordillera Vilcabamba, Peru)


Glacial lakes represent a threat for the populations of the Andes and numerous disastrous glacial lake outburst floods (GLOFs) occurred as a result of sudden dam failures or dam overtoppings triggered by landslides such as rock/ice avalanches into the lake. This paper investigates a landslide-triggered GLOF process chain that occurred on February 23, 2020, in the Cordillera Vilcabamba in the Peruvian Andes. An initial slide at the SW slope of Nevado Salkantay evolved into a rock/ice avalanche. The frontal part of this avalanche impacted the moraine-dammed Lake Salkantaycocha, triggering a displacement wave which overtopped and surficially eroded the dam. Dam overtopping resulted in a far-reaching GLOF causing fatalities and people missing in the valley downstream. We analyze the situations before and after the event as well as the dynamics of the upper portion of the GLOF process chain, based on field investigations, remotely sensed data, meteorological data and a computer simulation with a two-phase flow model. Comparison of pre- and post-event field photographs helped us to estimate the initial landslide volume of 1–2 million m3. Meteorological data suggest rainfall and/or melting/thawing processes as possible causes of the landslide. The simulation reveals that the landslide into the lake created a displacement wave of 27 m height. The GLOF peak discharge at the dam reached almost 10,000 m3/s. However, due to the high freeboard, less than 10% of the lake volume drained, and the lake level increased by 10–15 m, since the volume of landslide material deposited in the lake (roughly 1.3 million m3) was much larger than the volume of released water (57,000 m3, according to the simulation). The model results show a good fit with the observations, including the travel time to the uppermost village. The findings of this study serve as a contribution to the understanding of landslide-triggered GLOFs in changing high-mountain regions.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12


  • ANA (2014) Inventario Nacional de Glaciares y Lagunas. Ministerio de Agricultura y Riesgo, Autoridad Nacional del Agua, Unidad de Glaciología y Recursos Hídricos, Huaráz, Perú

  • Andrés N, Palacios D, Úbeda J, Alcalá J (2016) Ground thermal conditions at chachani volcano, southern peru. Geografiska Annaler: Series A, Phys Geogr 93(3):151–162

  • Beven K (1996) Equifinality and uncertainty in geomorphological modelling. In: The Scientific Nature of Geomorphology: Proceedings of the 27th Binghamton Symposium in Geomorphology, 27-29 September 1996:289–313. John Wiley & Sons

  • Bolch T, Peters J, Yegorov A, Prafhan B, Buchroithner M, Blagoveshchensky V (2011) Identification of potentially dangerous glacial lakes in the northern Tien Shan. Nat Hazards 59:1691–1714.

    Article  Google Scholar 

  • Breien H, De Blasio FV, Elverhoi A, Hoeg K (2008) Erosion and morphology of a debris flow caused by a glacial lake outburst flood, Western Norway. Landslides 5:271–280.

    Article  Google Scholar 

  • Carey M (2010) In the shadow of melting glaciers: climate change and Andean society. Oxford University Press

  • Carey M, Huggel C, Bury J, et al (2012) An integrated socio-environmental framework for climate change adaptation and glacier hazard management: Lessons from Lake 513, Cordillera Blanca, Peru. Clim Change 112:733–767

  • Carlotto V, Cárdenas J, Fidel L (2007) La Geología en la conservación de Machupicchu. Boletín Ingemmet, serie Patrimonio y Geoturismo

  • Clague JJ, O’Connor JE (2014) Glacier-related outburst floods. In: Haeberli W, Whiteman C (eds) Snow and ice-related hazards, risks and disasters. Elsevier, Amsterdam, pp 487–519.

    Chapter  Google Scholar 

  • COEN (2020) Informe de emergencia N°839-06/12/2020/COEN-INDECI, Aluvión en el distrito de Santa Teresa-Cusco

  • Emmer A (2017) Geomorphologically effective floods from moraine-dammed lakes in the Cordillera Blanca, Peru. Quat Sci Rev 177:220–234.

    Article  Google Scholar 

  • Emmer A, Vilímek V (2013) Review article: Lake and breach hazard assessment for moraine-dammed lakes: an example from the Cordillera Blanca (Peru). Nat Hazards Earth Syst Sci 13:1551–1565.

    Article  Google Scholar 

  • Emmer A, Merkl S, Mergili M (2015) Spatiotemporal patterns of high-mountain lakes and related hazards in western Austria. Geomorphology 246:602–616.

    Article  Google Scholar 

  • Emmer A, Harrison S, Mergili M, Allen S, Frey H, Huggel C (2020) 70 years of lake evolution and glacial lake outburst floods in the Cordillera Blanca (Peru) and implications for the future. Geomorphology 365:107178.

    Article  Google Scholar 

  • Emmer A, Vilímek V, Zapata ML (2018) Hazard mitigation of glacial lake outburst floods in the Cordillera Blanca (Peru): the effectiveness of remedial works. J Flood Risk Manag 11(S1):489–501.

    Article  Google Scholar 

  • Fischer L, Purves RS, Huggel C, et al (2012) On the influence of topographic, geological and cryospheric factors on rock avalanches and rockfalls in high-mountain areas. Nat Hazards Earth Syst Sci 12:241–254.

  • Frey H, Huggel C, Bühler Y, Buis D, Burga MD, Choquevilca W, Fernandez F, Hernández JG, Giráldez C, Loarte E, Masias P, Portocarrero C, Vicuña L, Walser M (2016) A robust debris-flow and GLOF risk management strategy for a data-scarce catchment in Santa Teresa, Peru. Landslides 13:1493–1507.

    Article  Google Scholar 

  • Froehlich DC (1995) Peak outflow from breached embankment dam. J Water Resour Plan Manage Div 121(1):90–97.

    Article  Google Scholar 

  • GAPHAZ (2017) Assessment of Glacier and Permafrost Hazards in Mountain Regions – Technical Guidance Document. Prepared by Allen S, Frey H, Huggel C et al. Standing Group on Glacier and Permafrost Hazards in Mountains (GAPHAZ) of the International Association of Cryospheric Sciences (IACS) and the International Permafrost Association (IPA). Zurich, Switzerland / Lima, Peru. 72 pp

  • Grabs WE, Hanisch J (1993) Objectives and prevention methods for glacier lake outburst floods (GLOFs). In: Snow and glacier hydrology (proceedings of the Kathmandu Symposium, November 1992). IAHS, Great Yarmouth, pp 341–352

    Google Scholar 

  • Gruber S, Haeberli W (2007) Permafrost in steep bedrock slopes and its temperature-related destabilization following climate change. J Geophys Res Earth Surf 112(F2):F02S18.

    Article  Google Scholar 

  • Haeberli W (1983) Frequency and characteristics of glacier floods in the Swiss Alps. Ann Glaciol 4:85–90.

    Article  Google Scholar 

  • Haeberli W (2005) Investigating glacier-permafrost relationships in high-mountain areas: historical background, selected examples and research needs. Geol Soc Lond, Spec Publ 242(1):29–37

    Article  Google Scholar 

  • Haeberli W, Schaub Y, Huggel C (2017) Increasing risks related to landslides from degrading permafrost into new lakes in de-glaciating mountain ranges. Geomorphology 293:405–417.

    Article  Google Scholar 

  • Hewitt K (1982) Natural dams and outburst floods in the Karakorum Himalaya. In: Glen JW (ed) Hydrological aspects of alpine and high-mountain areas. IAHS Publication 138, pp 259–269

  • Hewitt K, Liu J (2010) Ice-dammed lakes and outburst floods, Karakoram Himalaya: historical perspectives on emerging threats. Phys Geogr 31:528–551.

    Article  Google Scholar 

  • Huggel C, Kääb A, Haeberli W, Krummenacher B (2003) Regional-scale GIS-models for assessment of hazards from glacier lake outbursts: evaluation and application in the Swiss Alps. Nat Hazards Earth Syst Sci 3:647–662.

    Article  Google Scholar 

  • Huggel C, Carey M, Emmer A, Frey H, Walker-Crawford N, Wallimann-Helmer I (2020) Anthropogenic climate change and glacier lake outburst flood risk: local and global drivers and responsibilities for the case of lake Palcacocha, Peru. Nat Hazards Earth Syst Sci 20:2175–2193

    Article  Google Scholar 

  • IGM (1975) Mapa Geologico del Peru, escala 1:1,000,000. Instituto de Geologia and Mineria (IGM), Ministerio de Energia y Minas; Lima (Peru), 4 map sheets.

  • INGEMMET (2020): Inspección geológica y geodinámica en la laguna Salkantaycocha. Informe Técnico N° A7027, Instituto Geológico Minero y Metalúrgico, Perú.

  • Kougkoulos I, Cook SJ, Jomelli V, Clarke L, Symeonakis E, Dortch JM, Edwards LA, Merad M (2018) Use of multi-criteria decision analysis to identify potentially dangerous glacial lakes. Sci Total Environ 621:1453–1466.

    Article  Google Scholar 

  • Krautblatter M, Funk D, Günzel FK (2013) Why permafrost rocks become unstable: a rock–ice-mechanical model in time and space. Earth Surf Process Landf 38(8):876–887.

    Article  Google Scholar 

  • León H, Medina K, Loarte E, et al (2021) Mountain permafrost in the Tropical Andes of Peru: the 0°C isotherm as a potential indicator. In: Regional Conference on Permafrost, USA, 24–29 October 2021. USA

  • Mergili M, Fischer JT, Krenn J, Pudasaini SP (2017) r.avaflow v1, an advanced open source computational framework for the propagation and interaction of two-phase mass flows. Geosci Model Dev 10:553–569.

    Article  Google Scholar 

  • Mergili M, Frank B, Fischer JT, Huggel C, Pudasaini SP (2018) Computational experiments on the 1962 and 1970 landslide events at Huascarán (Peru) with r.avaflow: lessons learned for predictive mass flow simulations. Geomorphology 322:15–28.

    Article  Google Scholar 

  • Mergili M, Pudasaini SP (2020) r.avaflow – the open source mass flow simulation model. Last access: 6 January 2021

  • Mergili M, Schneider JF (2011) Regional-scale analysis of lake outburst hazards in the southwestern Pamir, Tajikistan, based on remote sensing and GIS. Nat Hazards Earth Syst Sci 11:1447–1462.

    Article  Google Scholar 

  • Mergili M, Müller JP, Schneider JF (2013) Spatio-temporal development of high-mountain lakes in the headwaters of the Amu Darya river (Central Asia). Glob Planet Chang 107:13–24.

    Article  Google Scholar 

  • Mergili M, Pudasaini SP, Emmer A, Fischer T, Cochachin A, Frey H (2020) Reconstruction of the 1941 GLOF process chain at Lake Palcacocha. Hydrol Earth Syst Sci 24:93–114.

    Article  Google Scholar 

  • Muñoz R, Huggel C, Frey H, Cochachin A, Haeberli W (2020) Glacial lake depth and volume estimation based on a large bathymetric dataset from the Cordillera Blanca, Peru. Earth Surf Process Landf 45:1510–1527.

    Article  Google Scholar 

  • Nie Y, Liu W, Liu Q, Hu X, Westoby MJ (2020) Reconstructing the Chongbaxia Tsho glacial lake outburst flood in the Eastern Himalaya: evolution, process and impacts. Geomorphology 370:107393.

    Article  Google Scholar 

  • Portocarrero C (2014) The glacial lake handbook: reducing risk from dangerous glacial lakes in the Cordillera Blanca. Peru. United States Agency for International Development, Washington

    Google Scholar 

  • Pudasaini SP, Mergili M (2019) A multi-phase mass flow model. J Geophys Res Earth Surf 124(12):2920–2942.

    Article  Google Scholar 

  • Reynolds JM (2003) Development of glacial hazard and risk minimisation protocols in rural environments. Reynolds Geo-Sciences Ltd., Flintshire

    Google Scholar 

  • Richardson SD, Reynolds JM (2000) An overview of glacial hazards in the Himalayas. Quat Int 65(66):31–47.

    Article  Google Scholar 

  • Sattar A, Goswami A, Kulkarni AV (2019a) Application of 1D and 2D hydrodynamic modeling to study glacial lake outburst flood (GLOF) and its impact on a hydropower station in Central Himalaya. Nat Hazards 97:535–553.

    Article  Google Scholar 

  • Sattar A, Goswami A, Kulkarni AV (2019b) Correction to: Application of 1D and 2D hydrodynamic modeling to study glacial lake outburst flood (GLOF) and its impact on a hydropower station in Central Himalaya. Nat Hazards 98:817

    Article  Google Scholar 

  • Schneider D, Huggel C, Cochachin A, Guillén S, García J (2014) Mapping hazards from glacier lake outburst floods based on modelling of process cascades at Lake 513, Carhuaz, Peru. Adv Geosci 35:145–155.

    Article  Google Scholar 

  • Porter SC (2013) Glaciations - neoglaciation in the American Cordilleras, In: Elias SA, Mock CJ (eds) Encyclopedia of Quaternary Science (2nd Edition), Elsevier.

  • Turzewski MD, Huntington KW, LeVeque RJ (2019) The geomorphic impact of outburst floods: integrating observations and numerical simulations of the 2000 Yigong flood, eastern Himalaya. J Geophys Res Earth Surf 124:1056–1079.

    Article  Google Scholar 

  • Vilca O (2019) Informe de inspección técnica Desborde de la laguna Chojñacota. Informe técnico, ODMRS, INAIGEM, Cusco, Perú

  • Vilca O (2020) Informe de inspección Laguna Salkantaycocha. Informe técnico, ODMRS, INAIGEM, Cusco, Perú

  • Wahl TL (2004) Uncertainty of Predictions of Embankment Dam Breach Parameters. J Hydraul Eng 130:389–397.

    Article  Google Scholar 

  • Worni R, Stoffel M, Huggel C, Volz C, Casteller A, Luckman B (2012) Analysis and dynamic modeling of a moraine failure and glacier lake outburst flood at Ventisquero Negro, Patagonian Andes (Argentina). J Hydrol 444–445:134–145.

    Article  Google Scholar 

  • Yoshikawa K, Úbeda J, Masías P, et al (2020) Current thermal state of permafrost in the southern peruvian andes and potential impact from El Niño–Southern Oscillation (ENSO). Permafr Periglac Process 31(4):598–609

Download references


The authors thank the editor and an anonymous reviewer for their valuable comments which helped to improve this article. Wen Jie Zhou kindly gave permission to use his photograph for Fig. 5a. Adam Emmer is a member of the RCUK-CONICYT (Research Council UK and National Commission for Scientific Research and Technology) Glacial Lakes of Peru (GLOP) project.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Oscar Vilca.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Vilca, O., Mergili, M., Emmer, A. et al. The 2020 glacial lake outburst flood process chain at Lake Salkantaycocha (Cordillera Vilcabamba, Peru). Landslides 18, 2211–2223 (2021).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • GLOF
  • High-mountain areas
  • Impact wave
  • Moraine-dammed lake
  • Process chain
  • Rock avalanche