Ice avalanche risk management from the Planpincieux glacier (Courmayeur - Italy)

Instabilities occurring on temperate glaciers in the Alps have been the subject of several studies, which have highlighted preliminary conditions and possible precursory signs of break-off events.

Since 2013, the Planpincieux Glacier, located on the Italian side of Mont Blanc massif (Aosta Valley), has been studied to analyse the dynamics of ice collapses in a temperate glacier.

These analyses have been conducted for several years, enabling the assessment of surface kinematics on the lower glacier portion and the different instability processes at the glacier terminus. During the period of the study, especially in the summer seasons, increases in velocities of the whole right side of the glacier tongue have been recorded. This fast sliding movement is mainly induced by water flow at the bottom of the glacier.

In 2019 summer season, the increase of speed coincided with the opening of a large crevasse, which outlined a fast moving ice volume, assessed by photogrammetric techniques as 250.000 m³.

According to the risk scenarios, the collapse of this ice volume from the glacial body would have reached the valley floor, potentially affecting the access road to the Val Ferret valley.

Considering the potential risk, a civil protection plan has been deployed by the monitoring team of the Aosta Valley Autonomous Region, Fondazione Montagna sicura and CNR-IRPI.

Glacier displacements, variations in the glacier morphology and environmental variables, such as air temperature, rain and snowfall, have all been taken into account to implement the monitoring plan.

This work outlines and summarises the steps used to develop the scientific knowledge into an integrated monitoring plan and a closure plan for the Val Ferret valley.