“When the snow started falling and it got dark/harder to breathe I was bricking it and thought I might die,” Shimmin wrote on Instagram. Shimmin and his group survived, although one member was sent to the hospital.
The avalanche was the second glacial meltdown of the week, demonstrating the dangers of human-caused climate change in the midst of a scorching summer in parts of Europe and Asia.
On July 3, a chunk of glacier as big as a building broke off in Italy’s Dolomites region and killed at least 11 hikers. The boulder separated from a melting glacier on Marmolada Mountain and triggered an avalanche of ice, rocks and debris below, where many tourists hike during the summer.
The avalanche in Italy came during a record heat wave during the country’s worst drought in 70 years, which was caused in part by a lack of winter snow in the mountains.
The researchers say these events underscore the dangers of a rapidly warming world and are set to increase unless greenhouse gas emissions are reduced.
Rising global temperatures are slowly weakening glacier systems in mountainous regions, where millions of people depend on these reservoirs as a source of fresh water. Climate change is also inducing more extreme heat waves, which can push weakened glacier systems overboard.
“There are no other directions the glaciers are going but to retreat” as global warming increases, said Peter Neff, a glaciologist at the University of Minnesota. “The feeling of the event in Italy and [Kyrgyzstan] does this happen more often.
Glacial events in Italy and Kyrgyzstan have similar backbones, said glaciologist Jeff Kargel. In the days before the Tian Shan Mountains collapsed, temperatures reached 59 degrees Fahrenheit (15 degrees Celsius) at nearly 12,000 feet (3,600 meters) above sea level. Likewise, temperatures soared around 50 degrees in the days before the fatal glacier crash in Italy. Both are examples of heat waves that have hit the northern hemisphere in recent months, some of which have been more intense and frequent due to climate change.
Both were also glacier ice avalanches, rather than primarily snow, in which a glacier ruptured and collapsed under the force of gravity. The high ice density added speed and weight to the avalanche.
During the Tian Shan event, Neff pointed out that there was no exposed snow around the mountain, so the avalanche was largely a solid piece of glacial ice. In high mountain regions with permafrost, warm temperatures destabilize not only the ice of the glacier but also the density of the ice around it. “It’s very dense, more like a landslide than an avalanche,” he said.
“The British backpacker is indeed, as he knows, very lucky to be alive in the case of the Kyrgyzstan event,” Kargel added.
Kargel said ice and snow detachments occur every spring and summer as glaciers approach the peak of their melting season, building up mass throughout the winter and gently flowing down a valley. Often, pieces of glacier become unstable, break off and produce ice avalanches.
Ice avalanches “happen all the time, and they would also happen without climate change,” Kargel said. “However, it seems, qualitatively, that there have been many, many more in recent years, in the last decade or so, than in previous decades.”
He said more deaths and damage from such events likely increased as more hikers, villages and infrastructure moved closer to these mountainous areas.
One of the most notable glacier collapses of the past decade, which Kargel remembers, occurred in 2016 in western Tibet, where all of the lower parts of two adjacent glaciers broke off within months of interval. One of the avalanches covered more than 3 square miles of ground and reached speeds of 90 mph, killing nine people and hundreds of animals. Kargel said both of these collapses “are almost certainly climate-related” because the glaciers experienced unusually high amounts of heavy rain and meltwater, which helped lubricate the underside of the glaciers.
While the glacier collapses in Kyrgyzstan and Italy were much smaller (about 1,000 times smaller in volume than other deadly glacier collapses), Kargel said they likely also had a link to climate change.
“A pretty strong hypothesis is that when temperatures get warmer [and] the climate is getting warmer, the amount of melting is increasing,” he said. “The effects of meltwater on destabilizing ice masses are increasing, and therefore the number, frequency and magnitude of glacial ice avalanches are expected to increase…and qualitatively this appears to be the case.”
Daniel Farinotti, glaciologist at ETH Zurich, agrees. “It has long been known that meltwater caused by high temperatures increases pressure in the subglacial drainage system of glaciers, which in turn can accelerate glacier movement,” Farinotti said in an e-mail. mail. “This increase in pressure and movement certainly has a role to play in such collapses.”
Among the biggest downstream effects of these mountain glacier losses and collapses are freshwater systems, Neff said. For example, high mountain glaciers in Asia play a vital role in delivering fresh water to river basins used for drinking, irrigation and hydroelectricity by nearly 1.5 billion people.
Mountain glaciers could have less ice than expected, straining freshwater supplies
” We put [these glaciers] in a state of change,” Neff said. “The ice will melt faster and deplete drinking water.”
And more meltdowns could occur as the melt season progresses.
“When the cast season starts in earnest, I would expect to see more,” Kargel said. “But hopefully there won’t be any other mortals.”