Rockfall frequency from French mountains has doubled since Little Ice Age
The Little Ice Age was a period of significant cooling from the early 14th to mid-19th centuries, which saw mean temperatures across the northern hemisphere drop by up to 2°C and the advancement of glaciers.
Such icy conditions had a marked imprint on the landscape and continue to the present day. New research, published in Earth and Planetary Science Letters, has considered how the Mont-Blanc massif in France has responded to changing environmental conditions since the termination of the Little Ice Age in the 1850s.
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The scientists explain this is due to intense permafrost action on the Mont-Blanc rockwalls below 3,800 meters above sea level. Here, water entering cracks in the rockwall freezes when temperatures drop, with the expanding ice causing the crack to widen; when the ice eventually thaws, the water travels further down into the crack and when it freezes again the cycle keeps repeating until eventually the rock splits entirely, leading to rockfall events.
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"At the current escalation rate, it's almost certain that the frequency of rockfalls in the Mont-Blanc massif will continue to increase," Dr. Courtial-Manent concludes.
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