Water accumulation dynamics of Tête Rousse glacier revealed by 3D-SNMR measurements

Between 2009 and 2018, we applied the three-dimensional Surface Nuclear Magnetic Resonance method (3D-SNMR) to the monitoring of water accumulation in the Tête Rousse glacier in French Alps. 3D-SNMR data allow for non-invasive observations of water and ice dynamics following three drainages of the accumulated water (2010, 2011 and 2012). We detected two principal reservoir in respectively the downhill and uphill zones of the glacier. After each drainage, meltwater refilled the downhill reservoir but its volume reduced. In 2018, the downhill reservoir contained about 10% of the volume relative that measured in 2010. In 2018, the water volume in the uphill reservoir was about 26,000 m 3. It makes about the half of the volume considered dangerous in 2009 when first detected in the downhill reservoir (50,000 m 3). The total volume assessed for the entire glacier in 2018 was about 31,500 m 3 against 24,800 m 3 measured in 2014. The increase in the volumes of the uphill zone accompanies a change in the geometry of the downhill cavern.