Processes governing the drainage of glacier-dammed lakes; combining field measurements and numerical modeling

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Jökulhlaups are sudden outburst floods caused by the unstable drainage of glacier-dammed lakes. During such an event, the discharge from a glacier can increase by more than one order of magnitude within a short time. Due to their widespread occurrence and their erratic nature, jökulhlaups pose a significant hazard potential and have often caused substantial damage. The assessment and prevention of natural hazards related to jökulhlaups require a reliable prediction of the nature, timing, duration and magnitude of the outburst flood. Despite the advances made in previous studies, there is still a lack of prognostic tools which capture the fundamental physics. In particular, the trigger mechanism remains incompletely understood and several aspects controlling the flood evolution are not satisfactorily explained. The proposed study will address these questions using a combination of numerical modeling and field measurements. Newly available computing tools enable now the solution of the full system of equations thereby facilitating the application of the model to realistic boundary conditions. Following a jökulhlaup in 2001, a lake dammed by Blamannsisen, a glacier in Norway, is currently filling again and is expected again and is expected to lead to another outburst flood in 2004. This site provides an excellent opportunity to collect the data necessary to define the boundary conditions for the numerical model and to validate its results.