Marmolada, glacier collapse: what happened

Study published on causes and mechanisms: huge volume of meltwater generated by highly anomalous temperatures

On 3 July 2022, approximately 64,000 tons of water, ice and rock debris suddenly detached from the Marmolada glacier in the Dolomites, giving rise to an avalanche that overwhelmed and killed 11 climbers, while 7 others were injured. An international team of researchers coordinated by Aldino Bondesan of the University of Padua has published the study The climate-driven disaster of the Marmolada Glacier (Italy) in the journal ‘Geomorphology’, also included in the highlights of ‘Nature’, which constitutes the first work who investigates the possible causes and mechanisms of the collapse.

The avalanche of ice and debris stopped in a gully after traveling about 2.3 km along the slope – reconstructs the university in a note – The collapse occurred in the upper part of the northern slope of the Marmolada at an altitude of 3213 m and involved a summit edge of the glacier, near Punta Rocca. This small residual glacier was an integral part of the large glacial front until about a decade ago, and today, due to the fragmentation caused by the retreat, it has remained isolated and enclosed within a niche on the north-facing slope just below the crest .

The event was documented by several videos recorded by hikers who were on site, which helped in the analysis of the causes of the collapse. The seismic energy released by the event was comparable to a magnitude 0.6 earthquake. “A detailed analysis of stereoscopic aerial and satellite images, taken before and after the event, allowed us to analyze the collapse modalities – explains Bondesan – The detachment was largely caused by a failure along a median crevasse, in part occupied by an enormous volume of meltwater generated by the highly anomalous temperatures of late spring and early summer. At the time of the event, 10.7 C had been reached at an altitude. properties of the basal rock surface have predisposed this glacial sector to collapse, the trigger of which is to be identified in the overlying pressure caused by the excess of melt water”.

“They were identified two concomitant mechanisms that caused the instability with consequent sudden collapse of the glacier: water seeping inside a glacier crevasse has caused it to be under such pressure that it lifts the layer of ice; when the water penetrated the basal sediments, there was buoyancy, as ice is less dense than water,” concludes Bondesan.