What is the link between melting permafrost and mountain instability?

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Melting Permafrost is Directly Linked to Increased Mountain Instability and Rockfalls

The exceptionally hot summer in the Alps has led to a record number of rockfalls, with a significant majority attributed to the climate crisis. Rising global temperatures are degrading and reducing permafrost, the "invisible" ice that has historically acted as a cement holding mountain rocks together. As this ice melts, it causes rocks to loosen and break away, leading to rockfalls.
Permafrost as a Natural Cement

For thousands of years, permafrost, in the form of ice lodged within rock cracks, has served a crucial role in maintaining the structural integrity of mountains. This ice acts like a natural cement, binding rock fragments and preventing them from dislodging. The stability of mountain slopes is thus intrinsically tied to the presence of this frozen water within the rock formations.
Temperature Rise and Ice Melt

The ongoing rise in global temperatures, a direct consequence of the climate crisis, is causing this permafrost ice to melt. When the temperatures increase, particularly during prolonged heatwaves like the one experienced in the Alps this summer, the ice within the rock cracks thaws. This melting process weakens the bonds holding the rocks together, making them susceptible to breaking loose.
Glacial Melt Exacerbates Instability

In addition to the melting of permafrost, the diminishing thickness of glaciers also contributes to mountain instability. Glaciers exert a stabilizing pressure on the rock walls they are in contact with. As these glaciers shrink and lose mass, this pressure is reduced, further increasing the likelihood of rockfalls and contributing to the overall destabilisation of mountain faces.
Record Rockfall Activity Observed

The consequences of this melting permafrost and glacial retreat are evident in the Alps, particularly around the Mont Blanc massif. This year is expected to be a record year for rockfalls, with an estimated 450 incidents recorded in the Mont Blanc massif alone. This figure is a stark increase from the few dozen recorded just 10 to 20 years ago, with the previous record of 300 set in 2022, another year marked by heatwaves.

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What is the link between melting permafrost and mountain instability?

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