Climate change is taking a toll on some of the most stable parts of the Tibetan Plateau.
The avalanche on July 17 is a case in point, when more than 70 million tons of ice from the Aru glacier in western Tibet tumbled down a valley, killing nine nomadic yak herders living there besides destroying property.
The connection between climate change and the disaster was mooted by a team of international researchers who published an analysis of the July 2016 avalanche disaster in Journal of Glaciology.
To explore what caused the avalanche, researchers from the Chinese Academy of Sciences collaborated with two glaciologists from the Ohio State University's Byrd Polar and Climate Research Center, professors Lonnie Thompson and Ellen Mosley-Thompson.
Huge Avalanche
According to NASA estimates, the debris of the Aru avalanche containing streams of ice and rock was spread across 4 square miles, with a thickness of nearly 98 feet. Aside from the yak herders, the casualties included 350 sheep and 110 yaks in the village of Dungru.
The debris spread makes it one of the most massive ice avalanches ever recorded. Comparable events include the avalanche from Kolka Glacier in the Caucasus in 2002, explained Andreas Kääb, a glaciologist at the University of Oslo.
Meltwater Likely Sped Up Ice Flow
Using satellite data and GPS, scientists have been investigating how much ice fell in the first avalanche and the area it covered.
The scientists noted that the avalanche only lasted for around 5 minutes but had buried 3.7 square miles of the valley floor within that short span of time. Thompson said the likely cause for the speed at which the ice came down could be meltwater at the glacier base that lubricated the ice.
Computer simulations also showed the only possibility was meltwater. Noting that the origin of the meltwater is still unknown, Thompson said the assumption is based on the average temperature at the nearest weather station, which has increased by about 1.5 degrees Celsius in the past 50 years. The warmer climate could have driven up the melting of snow and ice, resulting in the seeping down of meltwater beneath the glacier.
Noting that nearby glaciers are also vulnerable, Thompson said the unfortunate part is there is no mechanism to predict such disasters.
That sounds true as researchers were not able to predict the collapse of a neighboring glacier in the same mountain range in September.
Unprecedented In Western Tibet
Western Tibet is known as a stable region, unlike southern and eastern Tibet where glaciers are melting at a higher rate, which is why scientists are puzzled about the collapse of the Aru glacier.
This area on the Tibetan Plateau has even experienced excessive snowfall, which added to the mass of the glaciers.
Lead author of the paper Lide Tian, a glaciologist with the Institute of Tibetan Plateau Research, said the extra snowfall might have played a role in the avalanche by creating more meltwater, suggesting that once-stable regions could become extremely dangerous as climate change continues to accelerate glacier surging.
