A glacier in the Alps is at risk of an imminent collapse that would send up to 8.8 million cubic feet of ice sliding down the Mont Blanc massif. The risk has prompted precautionary road closures and evacuations on the Italian side.
Stefano Miserocchi, the mayor of the northern Italian town Courmayeur, issued an order on Tuesday evacuating mountain homes and closing two roads that pass near the Mont Blanc massif, a range that contains the highest peak in the Alps. The Planpincieux glacier is located on the southern slopes of the massif and is considered a hanging glacier because it is a remnant of a much larger glacial system that has retreated.
In the statement, Miserocchi said the glacier's precarious situation was due to climate change and ice melt.
“These phenomena testify once again how the mountain is in a phase of strong change due to climatic factors, therefore it is particularly vulnerable. In this case it is a temperate glacier particularly sensitive to high temperatures.”
The order came a day before a new IPCC special report reinforced that glaciers, snow, ice, and permafrost will continue to melt, causing small glaciers to lose up to 80% of their current ice mass by 2100. According to Italian media, about 50 cubic meters (over 1,700 cubic feet) fell from the Planpincieux glacier in 2017 without causing damage, though chunks “as large as a refrigerator” rolled down the mountain.
Speaking at the UN Climate Action Summit in New York on Tuesday, Italian Prime Minister Giuseppe Conte said, “The news that part of Mont Blanc risks collapsing is a warning that should not leave us indifferent. It must shake us all and force us to mobilize.”
In a statement, the city notes that between the end of August and the beginning of September, the lower part of the glacier was sliding at a speed of 50-60 cm (20-24 inches) per day. The moving area of the glacier lies directly below the mouth of a crevasse, the release states, and there has been “a significant increase in the sliding speed” recently, according to Miserocchi.
“This is just one example of how glaciers can become unstable as they respond to climate change and pass tipping points,” Grant Macdonald, a graduate student in glaciology at the University of Chicago, said in an email.
Macdonald explained that tipping points come about when glaciers lose more ice than usual in summer months and the melted ice flows away as meltwater, altering the glacier’s dynamics and stability.
“Melting and dynamical changes can lead to parts of the glacier becoming structurally unstable, and on mountain glaciers like this one that could mean parts ‘collapsing’. The effects of climate change could certainly promote this kind of behaviour,” he said.