Last year, a large, water-filled pocket in the Tête Rousse Glacier of the French Alps threatened to burst and flood the valley below. On an urgent request by local authorities, scientists quickly developed a model to assess whether draining the cavity would weaken the cavity roof and cause it to collapse. The model accurately predicted that draining would be safe.

Taking into account glacier geometry and the physical properties of ice, Olivier Gagliardini and his colleagues at the Joseph Fourier University in Grenoble, France, quantified a reasonably low risk of stress build-up that would burst the cavity during drainage. Measurements of glacial surface displacements taken during and after the successful drainage (pictured) confirmed the accuracy of the model's predictions.

Ice-flow models have become mature enough to be used in mitigating glaciological hazards, the team concludes.

Credit: J.-P. CLATOT/AFP/GETTY

Geophys. Res. Lett. doi:10.1029/2011GL047536 (2011)