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monitoring of glacial lake outburst floods (glofs) in chile - Planet Action

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PLANET ACTION DAY<br />

TOULOUSE, JUNE 9, 2009<br />

MONITORING OF GLACIAL LAKE<br />

OUTBURST FLOODS (GLOFS) IN CHILE<br />

RECENT DRAINAGE EVENTS OF<br />

GLACIAL LAKE CACHET 2, PATAGONIA<br />

G. Casassa (1*), J. Wendt (†), A. Wendt (1), P. López (1,2), J. Carrasco (3,1), A.<br />

Rivera (1,4,5), J. Leidich (6)<br />

(1) Centro de Estudios Científicos (CECS), Arturo Prat 514, Valdivia, Chile<br />

(†) Deceased<br />

(2) Hydrosciences Montpellier UMR 5569 (CNRS, IRD, UM1, UM2), Maison des Sciences de l’Eau, Université Montpellier 2, 34095 Montpellier<br />

Cedex 5, France<br />

(3) Dirección Meteorológica de Chile, Av. Portales 3450, Santiago, Chile<br />

(4) Centro de Ingeniería de la Innovación del CECS, Av. Prat 514, Valdivia, Chile<br />

(5) Departamento de Geografía, Universidad de Chile, Marcoleta 250, Santiago, Chile<br />

(6) Patagonia Adventure Expeditions, Riquelme 372, Coyhaique, Chile


PATAGONIA REGION<br />

Rignot et al. (2003)<br />

Holl<strong>in</strong> & Schill<strong>in</strong>g (1981)


GLACIAL LAKE OUTBURST FLOODS (GLOFs) IN<br />

CHILE 2007 - 2009<br />

Lake Cachet 2 (NPI)<br />

April 2008<br />

October 2008<br />

December 2008<br />

March 2009<br />

Lake Témpanos (SPI)<br />

April-May 2007


CECS’<br />

Airborne<br />

Mapp<strong>in</strong>g<br />

System<br />

(CAMS)<br />

• Riegl LMS-Q240<br />

Laser scanner<br />

• INS iMAR iNAV-FMS-<br />

Airsurf<br />

• GPS Javad Lexon<br />

GGD<br />

• Digital SLR Canon<br />

EOS 5D<br />

• CPU Fujitsu-<br />

Siemens Lifebook


DRAINAGE PATH OF LAKE CACHET 2


DIGITAL ELEVATION MODELS


BATHYMETRY OF LAKE CACHET 2<br />

Interpolated bathymetry pr<strong>of</strong>iles<br />

from May & October laser data<br />

Calculated <strong>lake</strong> volume = 0.2 km 3


VERTICAL PHOTO OF COLONIA GLACIER<br />

ACQUIRED WITH CAMS<br />

NOT<br />

ORTHORECTIFIED<br />

ORTHORECTIFIED


LAKE CACHET 2 SHOWING HIGH WATER LEVEL


LAKE CACHET 2 NEARLY EMPTY


LAKE CACHET 2 COMPLETELY EMPTY


NORTHERN SECTION OF LAKE CACHET 2


FRACTURES OF COLONIA GLACIER…


LAKE WATER DRAINAGE UNDER<br />

COLONIA GLACIER


LAKE COLONIA INMEDIATELY AFTER THE FLOOD<br />

OF APRIL 2008


WATER LEVEL AND T° OF BAKER RIVER DURING<br />

GLOF OF 7 APRIL 2008 OF LAKE CACHET 2<br />

Water level (m)<br />

7<br />

6<br />

5<br />

4<br />

3<br />

2<br />

3570 m 3 /s<br />

1200 m 3 /s<br />

1<br />

0<br />

01/04 02/04 03/04 04/04 05/04 06/04 07/04 08/04 09/04 10/04v<br />

14<br />

Water temperature (°C)<br />

12<br />

10<br />

8<br />

6<br />

4<br />

2<br />

4 °C<br />

0<br />

01/04 02/04 03/04 04/04 05/04 06/04 07/04 08/04 09/04 10/04


CONCLUSIONS<br />

• The Lake Cachet 2 <strong>outburst</strong> <strong>floods</strong> are typical <strong>glacial</strong><br />

<strong>lake</strong> <strong>outburst</strong> <strong>floods</strong> (GLOFs), or jökulhlaups produced by<br />

sudden dra<strong>in</strong>age via a sub<strong>glacial</strong> tunnel below Colonia<br />

Glacier.<br />

• The onset <strong>of</strong> dra<strong>in</strong>age is postulated to occur when the<br />

<strong>lake</strong> water level exceeds the ice overburden pressure <strong>of</strong><br />

Glaciar Colonia.<br />

• These are the first reported GLOF events from Lake<br />

Cachet 2, triggered <strong>in</strong>itially by climate warm<strong>in</strong>g. GLOFs at<br />

Lake Cachet 2 should cont<strong>in</strong>ue to occur periodically <strong>in</strong> the<br />

future until the ice th<strong>in</strong>s to such extent that a stable<br />

dra<strong>in</strong>age channel is created, for example at the eastern<br />

glacier marg<strong>in</strong>.


FUTURE WORK<br />

• More precise determ<strong>in</strong>ation <strong>of</strong> Lake Cachet II volume by<br />

means <strong>of</strong> airborne laser data <strong>of</strong> CECS-NASA-Armada<br />

mission <strong>of</strong> 8 October 2008, the same day <strong>of</strong> the GLOF<br />

event, when the <strong>lake</strong> was completely empty.<br />

• Airborne radar for ice thickness determ<strong>in</strong>ation.<br />

• Further water flow modell<strong>in</strong>g <strong>of</strong> the <strong>outburst</strong> flood us<strong>in</strong>g<br />

more precise <strong>lake</strong> and glacier geometry data from<br />

airborne laser and ice radar.<br />

• Deployment <strong>of</strong> <strong>lake</strong> level and river flow sensors, together<br />

with meteorological <strong>in</strong>struments and remote cameras for<br />

<strong>monitor<strong>in</strong>g</strong> and early prediction <strong>of</strong> GLOFs, <strong>in</strong><br />

collaboration with DGA.


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