1. NEW LAKES IN DE-GLACIATING HIGH-MOUNTAIN
REGIONS – A CHALLENGE FOR INTEGRATIVE
RESEARCH ABOUT RISK REDUCTION
AND SUSTAINABLE USE
Wilfried Haeberli,
Christian Huggel,
Yvonne Schaub,
Geography Department
University of Zurich
Foro Intercaional Glaciares

2. vanishing surface ice
de-buttressing
of lateral rock slopes
oversteepened
inside slope of
lateral moraine
disappearing support
of steep glacier parts,
ice avalanches from
steep hanging glaciers
ice avalanches
and rock falls not on
glacier tongue any more
but directly into lake
permafrost degradation
slope instability
Milhuacocha
Cordillera Blanca
Hegglin
lake formation
Foro Intercaional Glaciares

3. Changing
high-mountain
glaciers
Paul
Cordillera Blanca
Aletsch, Alps

4. Assumption: temperature increase of 4°C by 2100, time steps of 15 years
Scenario of glacier retreat and lake formation
Swiss Alps (Aletsch)

5. Aletsch
Swiss Alps
Schaub
Glaciers,
new lakes,
permafrost
and
steep slopes
in the Alps
Foro Intercaional Glaciares

6. Portocarrero
12.04.2010
A successfully
prevented
catastrophe
Nevado Hualcán
Cordillera Blanca
Portocarrero
Foro Intercaional Glaciares

7. Palcacocha, Peru
Modeling the process chain and
installation of an early warning system …
Nevado Hualcán
Cordillera Blanca
Schneider
Foro Intercaional Glaciares

8. Lake probably shallow
Lake probably deep
Lake formation uncertain
Lake formation ongoing or imminent
Lake formation in coming decades
possible retention
Hazard evolution
Carhuaz

9. Terrier
Terrier
Künzler
Hydropower and flood protection
Corbassiière
Swiss Alps
Foro Intercaional Glaciares

10. The long-term risks of destructive flood waves from new lakes
in deglaciating high-mountain regions are increasing …
… and need risk reduction strategies to be developed in time
because
• the number of new lakes increases with continued glacier retreat
• the new lakes are forming more and more closely to steep icy rock walls
• the stability of these steep icy rock walls tends to decrease
• the probability of large ice/rock avalanches into lakes increases
• impact waves in new lakes from slope instability become more frequent
• corresponding flood waves can affect valleys over long distances
• the hazard zone related to rock/ice avalanches is thereby extended
• areas of high vulnerability/damage potential may be affected
• the probability of dangerous events and the damage potential both grow
by
• modelling potential new lakes and critical slope conditions
• modelling potential process chains to delineate hazard zones
• defining hot spots of highest vulnerability
• using existing experience/practice of protection against impact waves
• considering aspects of long-term low probability/high damage risks
• envisaging possible synergies with hydropower, water supply, tourism