Glacier surging controls glacier lake formation and outburst floods: The example of the Khurdopin Glacier, Karakoram

Glacial lake outburst floods (GLOFs) have occurred across the planet throughout the Quaternary and are a significant geohazard in Arctic and alpine regions today. Iceland experiences more frequent GLOFs&#8212;known in Icelandic as j&#246;kulhlaups&#8212;than nearly anywhere on Earth, yet most research focuses on floods triggered by subglacial volcanic and geothermal activity. However, floods from proglacial lakes may be a better analogue to most global GLOFs.As the Icelandic Ice Sheet retreated across Iceland in the Late Pleistocene-Early Holocene, meltwater pooled at ice margins and periodically drained in j&#246;kulhlaups. Some of the most catastrophic floods drained from ice-dammed Glacial Lake Kj&#246;lur, surging across southwestern Iceland from the interior highlands to the Atlantic Ocean. These floods left extensive geomorphologic evidence along the modern-day course of the Hv&#237;t&#225; River, including canyons, scoured bedrock, boulder deposits, and Gullfoss&#8212;Iceland&#8217;s most famous waterfall. The largest events reached an estimated maximum peak discharge of 300,000 m3 s-1, ranking them among the largest known floods in Iceland and on Earth.Yet, all our evidence for the Kj&#246;lur j&#246;kulhlaups comes from only one publication to date (T&#243;masson, 1993). My research employs new methods to better constrain flood timing, routing, magnitude, and recurrence interval at this underexplored site. This talk presents new and synthesized j&#246;kulhlaup geomorphologic evidence; HEC-RAS hydraulic modeling results of flow magnitude and routing; and ongoing geochronological analyses using cosmogenic nuclide exposure dating and tephrochronology. It also situates these events within Icelandic Ice Sheet deglaciation chronology and environmental change at the Pleistocene-Holocene transition. Finally, it examines the Kj&#246;lur floods as an analogue to contemporary ice sheet response, proglacial lake formation, and j&#246;kulhlaup processes and landscape evolution in Arctic and alpine regions worldwide, where GLOFs pose an increasing risk to downstream communities due to climate-driven meltwater lake expansion. &#160;Citation: T&#243;masson, H., 1993. J&#246;kulst&#237;flu&#240; v&#246;tn &#225; Kili og hamfarahlaup &#237; Hv&#237;t&#225; &#237; &#193;rness&#253;slu. N&#225;tt&#250;rufr&#230;&#240;ingurinn 62, 77-98.

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Climate change and the global pattern of moraine-dammed glacial lake outburst floods

10.5194/tc-2017-203 ◽

2017 ◽

Cited By ~ 3

Author(s):

Stephan Harrison ◽

Jeffrey S. Kargel ◽

Christian Huggel ◽

John Reynolds ◽

Dan H. Shugar ◽

...

Keyword(s):

Climate Change ◽

Ice Age ◽

Dam Failure ◽

Glacial Lake ◽

Glacier Recession ◽

Outburst Floods ◽

Glacial Lake Outburst Floods ◽

Lake Formation ◽

Recent Climate ◽

Moraine Dam Failure

Abstract. Despite recent research identifying a clear anthropogenic impact on glacier recession, the effect of recent climate change on glacier-related hazards is at present unclear. Here we present the first global spatio-temporal assessment of glacial lake outburst floods (GLOFs) focusing explicitly on lake drainage following moraine dam failure. These floods occur as mountain glaciers recede and downwaste and many have an enormous impact on downstream communities and infrastructure. Our assessment of GLOFs associated with the collapse of moraine-dammed lakes provides insights into the historical trends of GLOFs and their distributions under current and future global climate change. We observe a clear global increase in GLOF frequency and their regularity around 1930, which likely represents a lagged response to post-Little Ice Age warming. Notably, we also show that GLOF frequency and their regularity – rather unexpectedly – has declined in recent decades even during a time of rapid glacier recession. Although previous studies have suggested that GLOFs will increase in response to climate warming and glacier recession, our global results demonstrate that this has not yet clearly happened. From assessment of the timing of climate forcing, lag times in glacier recession, lake formation and moraine dam failure, we predict increased GLOF frequencies during the next decades and into the 22nd century.

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Climate change and the global pattern of moraine-dammed glacial lake outburst floods

The Cryosphere ◽

10.5194/tc-12-1195-2018 ◽

2018 ◽

Vol 12 (4) ◽

pp. 1195-1209 ◽

Cited By ~ 64

Author(s):

Stephan Harrison ◽

Jeffrey S. Kargel ◽

Christian Huggel ◽

John Reynolds ◽

Dan H. Shugar ◽

...

Keyword(s):

Climate Change ◽

Ice Age ◽

Dam Failure ◽

Glacial Lake ◽

Glacier Recession ◽

Outburst Floods ◽

Glacial Lake Outburst Floods ◽

Lake Formation ◽

Recent Climate ◽

Moraine Dam Failure

Abstract. Despite recent research identifying a clear anthropogenic impact on glacier recession, the effect of recent climate change on glacier-related hazards is at present unclear. Here we present the first global spatio-temporal assessment of glacial lake outburst floods (GLOFs) focusing explicitly on lake drainage following moraine dam failure. These floods occur as mountain glaciers recede and downwaste. GLOFs can have an enormous impact on downstream communities and infrastructure. Our assessment of GLOFs associated with the rapid drainage of moraine-dammed lakes provides insights into the historical trends of GLOFs and their distributions under current and future global climate change. We observe a clear global increase in GLOF frequency and their regularity around 1930, which likely represents a lagged response to post-Little Ice Age warming. Notably, we also show that GLOF frequency and regularity – rather unexpectedly – have declined in recent decades even during a time of rapid glacier recession. Although previous studies have suggested that GLOFs will increase in response to climate warming and glacier recession, our global results demonstrate that this has not yet clearly happened. From an assessment of the timing of climate forcing, lag times in glacier recession, lake formation and moraine-dam failure, we predict increased GLOF frequencies during the next decades and into the 22nd century.

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Risk estimation for future glacier lake outburst floods based on local land-use changes

Natural Hazards and Earth System Science ◽

10.5194/nhess-14-1611-2014 ◽

2014 ◽

Vol 14 (6) ◽

pp. 1611-1624 ◽

Cited By ~ 16

Author(s):

S. Nussbaumer ◽

Y. Schaub ◽

C. Huggel ◽

A. Walz

Keyword(s):

Land Use ◽

Land Use Planning ◽

Driving Forces ◽

Local Level ◽

Land Use Changes ◽

Management Strategies ◽

High Mountain ◽

Damage Potential ◽

Outburst Floods ◽

Lake Formation

Abstract. Effects of climate change are particularly strong in high-mountain regions. Most visibly, glaciers are shrinking at a rapid pace, and as a consequence, glacier lakes are forming or growing. At the same time the stability of mountain slopes is reduced by glacier retreat, permafrost thaw and other factors, resulting in an increasing landslide hazard which can potentially impact lakes and therewith trigger far-reaching and devastating outburst floods. To manage risks from existing or future lakes, strategies need to be developed to plan in time for adequate risk reduction measures at a local level. However, methods to assess risks from future lake outbursts are not available and need to be developed to evaluate both future hazard and future damage potential. Here a method is presented to estimate future risks related to glacier lake outbursts for a local site in southern Switzerland (Naters, Valais). To generate two hazard scenarios, glacier shrinkage and lake formation modelling was applied, combined with simple flood modelling and field work. Furthermore, a land-use model was developed to quantify and allocate land-use changes based on local-to-regional storylines and three scenarios of land-use driving forces. Results are conceptualized in a matrix of three land-use and two hazard scenarios for the year 2045, and show the distribution of risk in the community of Naters, including high and very high risk areas. The study underlines the importance of combined risk management strategies focusing on land-use planning, on vulnerability reduction, as well as on structural measures (where necessary) to effectively reduce future risks related to lake outburst floods.

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Characterization of Kyagar Glacier and Lake Outburst Floods in 2018 Based on Time-Series Sentinel-1A Data

Water ◽

10.3390/w12010184 ◽

2020 ◽

Vol 12 (1) ◽

pp. 184 ◽

Cited By ~ 2

Author(s):

Meimei Zhang ◽

Fang Chen ◽

Bangsen Tian ◽

Dong Liang ◽

Aqiang Yang

Keyword(s):

Time Series ◽

Early Recognition ◽

Maximum Velocity ◽

Glacial Lake ◽

Valuable Insight ◽

Glacier Surface ◽

Glacier Terminus ◽

Outburst Floods ◽

Lake Formation ◽

Glacier Velocity

Early recognition of glacial lake outburst floods (GLOFs) is required for timely and cost-effective remedial efforts to be implemented. Although the formation of ice-dammed lakes is known to begin as a pond or river that was blocked by ice from the glacier terminus, the relationship between glacier dynamics and lake development is not well understood. Using a time-series of Sentinel-1A synthetic aperture radar (SAR) data acquired just before and after the lake outburst event in 2018, information is presented on the dynamic characteristics of Kyagar Glacier and its ice-dammed lake. Glacier velocity data derived from interferometry show that the glacier tongue experienced an accelerated advance (maximum velocity of 20 cm/day) just one month before the lake outburst, and a decreased velocity (maximum of 13 cm/day) afterward. Interferometric and backscattering properties of this region provide valuable insight into the diverse glaciated environment. Furthermore, daily temperature and total precipitation data derived from the ECMWF re-analysis (ERA)Interim highlight the importance of the sustained high-temperature driving force, supporting empirical observations from previous studies. The spatial and temporal resolution offered by the Sentinel-1A data allows variations in the glacier surface motion and lake evolution to be detected, meaning that the interaction mechanism between the glacial lake and the associated glacier can be explored. Although the glacier surge provided the boundary conditions favorable for lake formation, the short-term high temperatures and precipitation caused the melting of ice dams and also a rapid increase in the amount of water stored, which accelerated the potential for a lake outburst.

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Local land-use change based risk estimation for future glacier lake outburst flood

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-1-4349-2013 ◽

2013 ◽

Vol 1 (4) ◽

pp. 4349-4387

Author(s):

S. Nussbaumer ◽

C. Huggel ◽

Y. Schaub ◽

A. Walz

Keyword(s):

Land Use ◽

Land Use Planning ◽

Driving Forces ◽

Risk Estimation ◽

Local Level ◽

Land Use Changes ◽

High Mountain ◽

Damage Potential ◽

Outburst Floods ◽

Lake Formation

Abstract. Effects of climate change are particularly strong in high-mountain regions. Most visibly, glaciers are shrinking at a rapid pace, and as a consequence, glacier lakes are forming or growing. At the same time the stability of mountain slopes is reduced by glacier retreat, permafrost thaw and other factors, resulting in an increasing risk of landslides which can potentially impact lakes and therewith trigger far reaching and devastating outburst floods. To manage risks from existing or future lakes, strategies need to be developed to plan in time for adequate risk reduction measures at a local level. However, methods to assess risks from future lake outbursts are not available. It is actually a challenge to develop methods to evaluate both, future hazard potential and future damage potential. Here we present an analysis of future risks related to glacier lake outbursts for a local site in southern Switzerland (Naters, Valais). To estimate two hazard scenarios, we used glacier shrinkage and lake formation modelling, simple flood modelling and field work. Further we developed a land-use model to quantify and allocate land-use changes based on local-to-regional storylines and three scenarios of land-use driving forces. Results are conceptualized in a matrix of three land-use and two hazard scenarios for a time period of 2045, and show the distribution of risk in the community of Naters, including high and very high risk areas. The study corroborates the importance of land-use planning to effectively reduce future risks related to lake outburst floods.

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