For mountaineers in the Mont Blanc massif, the climbing season has been disappointing so far. This is not only due to a lack of snow but also because huge sections of rock face have fallen down this summer.
For this reason, the three main regular routes to the summit of Mont Blanc are temporarily closed. Many overnight accommodations for climbers are keeping their doors shut.
A week ago, a 31-year-old alpinist died in Haute-Savoie after being hit by a falling rock. It was the third fatality within 24 hours in the Mont Blanc massif. The risk of rock avalanches in the mountains is greater during long periods of drought.
'Dramatic season'
Jelle Staleman (44) is a Dutch ski and mountain guide working in the area. He is currently on the Italian side of Mont Blanc.
"It has been raining all day today, and I am quite happy about that," he says. "There has been hardly any snow or rain here for about sixty days. That is really unique. This is the most dramatic season I have experienced in twenty years in the Alps."
He mainly sees a large shortage of snow, especially on the glaciers. "In the past, you could walk out of the hut and everything was frozen. You had to go outside with a hat and gloves. Now that is often no longer the case. Even at 4000 meters altitude, the temperature regularly hovers around freezing point."
Because glaciers melt faster at the bottom than higher up, they are becoming steeper. This increases the chance of icefall: large pieces of ice breaking off and crashing down.
"To safely cross a glacier crevasse, the snow layer above it must be well frozen," says Staleman.
Those who know what they are doing, go out with a guide, and are roped together, are usually not immediately in mortal danger if they fall into a crevasse. "Still, it is safer to cross a glacier at temperatures below freezing, especially at night."
'Apocalyptic'
In addition, Staleman sees an exceptional number of rock avalanches in the Alps this season. "That happens every summer, but this year they are much larger. Their scale can almost be called apocalyptic. Some rock blocks I see in footage are as large as a house or a car."
Several guides in the Alps have experienced such moments:
According to Staleman, the cause lies in the permafrost, a permanently frozen soil layer that acts like cement holding the mountains together. "If the zero-degree boundary remains unusually high for a long time, that layer disappears. That can have irreversible consequences. When the permafrost melts away, rock blocks loosen and the number of rock avalanches increases."
What causes a rock avalanche?
Earth scientist Tjalling de Haas (Utrecht University) researches rock avalanches. "A rock face is never a single whole; there are cracks running through it. Water enters there, and that water freezes. With permafrost, it remains permanently frozen. That ice holds the mountain together like a kind of glue."
Due to climate change, the permafrost thaws higher and higher in the mountains. "As a result, sometimes the last piece that still holds such a rock face together disappears, and then you get these kinds of collapses."
At Mont Blanc, the destabilizing effect of melting glaciers also plays a role. "The ice of glaciers presses against a rock face. When the glacier melts, this pressure disappears and the rock expands. This leads to instability and increases the risk of rock avalanches."
The Italian route to Mont Blanc has been closed since mid-July due to dangerous glacier crevasses, says Staleman. "Clients sometimes train for months and spend thousands of euros on a trip to the summit. It is frustrating when a route is closed, but sometimes it is necessary."
Owners of mountain huts where alpinists stay are also affected. "Many huts depend on meltwater from glaciers or rainwater. If that does not come, some huts have to close earlier."
The conditions on Mont Blanc have been such for years that Staleman no longer offers climbs in July and August. In other parts of the massif, trips are often still possible, although it is common that the route must be adjusted during these months.
"It is constant improvisation. Where twenty years ago we could carry out about 80 percent of our original plans, nowadays we have to adjust half of them."