Preliminary observation of Marmolada glacier collapse of July 2022 with space-based cameras

On 3 July 2022, a section of the Marmolada glacier (Marmolada Group, Fassa Dolomites, Southern Limestone Alps) collapsed, causing an ice avalanche resulting in the death of 11 alpinists. Before the event, there were no clear signs of any potential collapse, and no warning notices were broadcasted; due to the velocity of the avalanche, no escape was possible for the involved persons. In this work, a preliminary analysis of the Marmolada glacier collapse is performed with four optical channels space imaging provided by Planet Labs, with resolution of 3 m per pixel. Pre- and post-event satellite observations are employed to assess the areas involved in the event: multispectral images can be compared to identify the collapse area and the debris conoid. A first estimation suggests a collapse area of about 4800 m(2) and a collapse volume of about 96,000 m(3). In addition, historical data from the Planet Labs optical pictures database can be employed to compare the status of the detached glacier and the evolution of the crevasses on its surface.