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Collapse at 200km/h: Birch Glacier Disaster Exposes the Violent Face of Global Warming

Published on June 10, 2025 by Krishna Pathak

Anatomy of a Glacier’s Collapse

Anatomy of a Glacier’s Collapse

Over several years, large rockfalls from the nearby Nesthorn Mountain landed on the glacier’s front. These rocks piled up and formed a thick blanket. When only a thin layer of dust or dirt settles on a glacier, it absorbs sunlight and causes the ice to melt faster. But if the layer becomes thick enough — as it did here — it does the opposite. It insulates the ice, reducing how much melts. Between 2017 and 2023, the front part of the glacier gained about 15 meters in thickness and moved forward by roughly 50 meters. While the top part of the glacier was still thinning due to heat, the lower part was growing dangerously large and heavy. On May 17, a massive rockslide from Nesthorn added even more weight. The rocks increased pressure on the glacier’s surface and squeezed out meltwater inside. Rainfall in the days that followed only worsened the situation. Once the glacier began sliding, it created more heat from friction, which produced even more meltwater underneath. Eventually, the bottom lost its grip, and

A New Category of Avalanches

A New Category of Avalanches

The Birch Glacier event belongs to a newly studied group of disasters. Scientists now refer to them as “sudden large-volume detachments of low-angle mountain glaciers.” These are different from typical avalanches, which happen on steep slopes and mostly involve snow. These glacier collapses occur on much gentler slopes — some as low as 10 to 20 degrees. The collapse is not just about snow or ice. It includes rocks, mud, and water, all mixing together into a fast-moving, destructive flow. Since 1990, experts have tracked at least 20 such events across the globe. Birch Glacier is now one of them, and its behavior matches the pattern observed in similar past disasters.

Kolka, Russia/Georgia Border

Kolka, Russia/Georgia Border

The deadliest of such glacier collapses in recent times happened in 2002 at Kolka Glacier, located in the Caucasus Mountains. After a massive rockfall, a glacier section — 40 times larger than Birch Glacier’s lower part — detached and rushed downhill. The glacier sat on a 13-degree slope. The flow of ice, rock, and mud traveled over 16 kilometers and buried a nearby village. More than 125 people lost their lives. Kolka showed how deadly these collapses can be when they occur without enough warning.

Aru, Tibet

Aru, Tibet

In 2016, two giant glacier collapses happened just weeks apart in the Aru mountain range of Tibet. Each release involved massive rock-ice flows traveling long distances across relatively flat land. Tibet’s high-altitude glaciers, once considered stable, are now changing due to unexpected rain and melting. These events shocked the scientific community and revealed the growing risks in other cold, dry mountain areas.

Tinguiririca, Chile

Tinguiririca, Chile

Glacier collapses occurred in 1994 and 2007 in Chile’s Andes Mountains near Tinguiririca. Though these events caused no deaths, they damaged infrastructure like mountain roads and blocked access to communities. These cases highlighted how mild slopes can still produce powerful glacial avalanches when overloaded by rockfalls and rainfall.

Rasht, Tajikistan

Rasht, Tajikistan

In the Rasht Valley of Tajikistan, glacial collapses struck twice in recent years — in 2017 and 2019. These events matched the same pattern: rockfalls combined with unexpected high-altitude rainfall, followed by sudden sliding. Thanks to early warnings, villagers were spared. But the incidents showed how even small glaciers in remote valleys can become dangerous in the right conditions.

Aparejo, Chile

Aparejo, Chile

In 1980, a glacier in the Aparejo region of Chile broke off and caused a significant rock-ice avalanche. It started on a low-angle glacier and rushed down quickly, covering roads and isolating communities. Though the region has long experience with snow avalanches, this event was unusual in its mixture of rock and ice — a warning sign seen in many recent glacier disasters.

Tsambaragav, Mongolia

Tsambaragav, Mongolia

This collapse happened in 1988 in a rarely studied part of Mongolia. Without earthquakes or major storms, a glacier failed after years of rock buildup and hidden melting. The flow traveled rapidly and damaged local pastureland. Though less populated, the area showed that no mountain region is entirely safe from this type of event.

Devdorak, Caucasus

Devdorak, Caucasus

Before the Kolka disaster, other collapses were reported from the nearby Devdorak Glacier in the 18th and 19th centuries. Multiple rock-ice avalanches devastated parts of the region. These cases mirror recent ones in terms of low-angle slopes and buildup of pressure from rockfalls and meltwater. The area remains one of the most closely watched zones for future glacial hazards.

Leñas, Argentina

Leñas, Argentina

In 2007, Argentina’s Leñas Valley experienced a glacial collapse caused by rainfall and rock pressure. The glacier had a gentle slope but failed after weeks of stress buildup. Property damage was reported, but the impact was lessened by timely evacuation. It became one more case confirming the risk posed by these new avalanche types.

The Climate Link to Glacial Detachments

The Climate Link to Glacial Detachments

Climate change connects nearly all of these disasters. As temperatures rise, glaciers melt from both above and below. Meltwater builds up inside, weakening the glacier’s structure. Rainfall is now appearing at higher elevations where snow once dominated. Permafrost — the frozen ground in alpine regions — is thawing too. As it melts, rock walls that were once solid begin to crumble. The falling rocks land on glaciers and increase pressure on the ice. In many of the collapses mentioned, this chain reaction led to disaster. Glaciers like Birch are becoming more unstable not just from warming alone, but from the complex effects of a changing climate. Melting, rain, rockfalls, and even insulation from debris are creating a perfect storm in mountain regions. These aren’t isolated events. Scientists now know that many glaciers worldwide may face similar risks — even if they’ve never failed before. The threat is growing, and the evidence is already visible in the scars left behind.

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