Why Are Giant Rocks Suddenly Flying Down Mountains in the Dolomites?
Car-sized boulders have been tumbling down the Italian Dolomites this summer, bouncing into valleys, cutting off roads, and forcing hikers to evacuate popular trails. Entire pinnacles have broken away in recent months, including sections of Cima Falkner, which sent thousands of tons of rock crashing downslope at the end of July. Officials have scrambled to close climbing routes, while locals describe hearing thunderous cracks and seeing dust clouds rise from mountainsides. The question many are asking is, why now?
Fragile Foundations
Image via iStockphoto/Schroptschop
The Dolomites are made of dolomia stone sitting on a base of clay. This combination creates conditions where towers and ridges slowly tilt and rotate under their own weight. Once enough stress builds, a diagonal fracture opens, and the block separates from the main formation. The Trephor Tower collapse in 2004, one of the iconic Five Towers, was a striking example. At over 10,000 cubic meters, it was the size of the Leaning Tower of Pisa laid flat. Since then, collapses have been documented at Grand Vernel, Croda Marcora, Sassolungo, and other famous peaks.
In Belluno province alone, more than 6,000 landslides have been recorded since the Middle Ages. The debris has shaped the Dolomites’ jagged skyline, leaving the spires and sheer walls that attract climbers and hikers today. But recent activity suggests that the cycle is accelerating.
A Summer Of Rockfalls
In late July 2025, around 36,000 cubic meters of rock broke loose on Cima Falkner. Authorities estimated that up to 70,000 cubic meters remain unstable, prompting the closure of routes 305, 315, 316, and 331. Some routes reopened after inspections, others remain blocked due to ongoing instability.
Broken rocks from Peak Faulkner had totaled 300,000–400,000 cubic meters at the start of August. At Monte Pelmo, locals reported hearing booming cracks before pinnacles gave way, scattering dust and rubble into the valleys below.
By mid-August, rockfalls were being reported almost weekly, disrupting traffic and forcing temporary evacuations. For a region preparing to host the 2026 Winter Olympics, the timing is raising serious concerns.
Stress From Above
Scientists studying the Dolomites point to stressors that weaken already fragile formations. Intense rainfall has increased in recent decades, with maximum precipitation levels rising 5 to 20 percent compared with 30 to 40 years ago. Water seeps into cracks, then freezes and expands, prying rock apart. The freeze-thaw process repeats more frequently now, creating fractures that destabilize massive blocks.
Once fractured, rock surfaces also heat and cool more rapidly, further increasing instability. Geologists compare this to the surface of a radiator: the more sections exposed, the faster temperatures shift. This cycle weakens the rock and brings down sections that once seemed stable.
At higher altitudes, permafrost once acted as a natural glue, holding fractured rock together. That glue is now disappearing. The collapse of the Marmolada glacier in 2022, which killed 11 people, was one early warning. In 2025, experts warned that Marmolada could vanish completely by 2040 after losing 70 hectares of ice in just five years. The same warming trend is now undermining the structure of the Dolomite peaks.
Geologists stress that mountains are never permanent. But the pace of collapses this year has been remarkable. Italian Alpine Club officials note that “never before” have they recorded such an increase in rockfalls.
Living With Instability
Authorities acknowledge there is no engineering fix to hold the Dolomites in place. Instead, they rely on monitoring systems, drones, and sensors that track vibrations and cracks. In Trentino, rescue teams evacuated hundreds of hikers from Cima Falkner in early August, moving them to chairlift stations and refuges before conditions worsened. Councils continue to enforce trail closures, despite pressure from tourism.
For guides and climbers, the changes demand constant adaptation. Routes have been shifted, itineraries modified, and risk assessments tightened. Yet guides admit that skill and caution only go so far when entire walls break free.
The Dolomites’ status as a UNESCO World Heritage Site reflects their natural evolution, not permanence. These mountains have always reshaped themselves through landslides and erosion. What stands out today is the rapid pace of those changes and the uncertainty it brings to communities and visitors alike.