A 21 trillion cubic foot glacier avalanche came down near Dungari village, a remote area of Tibet, on July 17th, 2016 killing 9 people, 100 sheep, and 350 yaks (see photos above & below).  This avalanche was 3.7 miles long and up to 100 feet deep.

Then, the impossible happened: another approximately 20 trillion cubic foot glacier avalanche came down in the exact same region in late September 2016.  

Two of these enormous ice avalanches in the same region within 2.5 months is unheard of.

“Even one of these gigantic glacier avalanches is very unusual.  Two of them within close geographical and temporal vicinity is, to our best knowledge, unprecedented.” – Andreas Kääb, a glaciologist at the University of Oslo.

Although scientists are not entirely sure what happened, it seems probable that a build-up of meltwater underneath the glaciers caused the two collapses. Scientists, baffled by the first avalanche, quickly launched a study into into its origins. Studying a record of satellite data for changes, they noted a series of signature crevasses at the head of the glacier and a rapid advance called surging, in which a glacier can move 10-100 times faster than normal.

The surging began in Sept. 2015, and stopped at a few months. Computer models and scientists speculate that terrain features halted the rapid advance of the glacier and caused an accumulation of meltwater. The glacier then spectacularly collapsed, killing 9 people and hundreds of livestock. While meltwater often contributes to glacial surging, as in the Greenland ice sheet, it rarely if ever causes a glacial collapse of this magnitude.

Using data from the last avalanche, scientists were able to predict the second. Most notably, the same signature crevasses began to appear at the head of the glacier. A warning was sent to the Chinese government, but it was too late; the glacier had collapsed just a few hours before the warning.

Scientists are in agreement that long term climate change is responsible for this unprecedented series of events, but continue to search for more precise causes. The similarities between the events suggest that shared factors, such as geographical features, long term climate, and shorter term weather conditions, probably contributed to the events.

“The risk of natural hazards is amplified in the mountains and by the mountains.  And climate change generally acts to enhance these risks even further.” – Joseph Shea, a scientist at the International Centre for Integrated Mountain Development, told Climate Central after the first avalanche

BEFORE & AFTER PHOTOS: