Summer Rupper

Development, Climate Change, and Hazards in the Himalayas

You see the dust first, a massive cloud that blooms from behind the mountain ridge. The ground rumbles underfoot while a deep groan echoes through the valley, as if the very mountains are in pain. Then comes the flood, a ravenous beast hundreds of feet high that tears through the valley. It consumes the hydropower plant below in an instant, leaving nothing behind. All you can do is watch as the raging waters decimate everything in their path.

Where did the flood come from? Was there more to come? And was it safe to send rescue workers or to transport supplies to the mountainous village of Raini, now isolated from the world by the flood that destroyed all of their bridges? Scientists all over the world scrambled to answer these questions. Time was running out.

Dr. Summer Rupper is a glaciologist who has studied extensively the effects of climate change in the Himalayas. She graduated from BYU in geology and received her master's and PhD in Earth and Space Sciences from the University of Washington. She taught at BYU for a number of years and now teaches at the University of Utah. Due to her prior research in the Himalayas, she was one of the first scientists contacted after the flood on February 7th, 2021. For the next several weeks she would help lead a scientific effort involving more than 70 collaborators, including 51 authors from 47 institutions spanning 14 countries and combining 8 disciplines. It was a uniquely open effort with no concern over who would get credit. Their goal was simply to provide answers and prevent further catastrophe as fast as possible.

The main problem was that no one knew where the flood originated. Scientists were able to use satellite and helicopter photos to map the course of the flood and find its starting point. They tracked the path of the wreckage, including deposits of muck along the flood path, layers of dust from the accompanying cloud, and even trees felled by the blast wave. At the origin point, they found a single glacier—or at least, they found the absence of one. Satellite images showed that a massive glacier had formed on the side of a mountain and had been there up until at least February 5th. But by February 10th, the glacier was gone. Their first proposal was that the glacier fell and dammed the river, resulting in a backup that eventually collapsed, resulting in the catastrophic flood.

They used local seismic data to pinpoint the exact time that the glacier fell from the only two seismic stations in the area. Three stations would have been ideal to be able to triangulate and distinguish the fall in the seismically loud area, but they got lucky. Those five days were unusually quiet until the glacier fell. However, the data showed that the glacier collapsed only nine minutes before the flood hit Raini, not nearly enough time to dam the river and build up water. A dead end.

Still, the fact that the collapse of the glacier was so close to the event of the flood could not have been coincidental. They examined the glacier itself, attempting to determine if it had enough water to explain the flood volume. Hanging glaciers such as this one are fundamentally unstable, and satellite records show that it had collapsed multiple times over the years—but those were mostly ice. In order to cause a flood, you need about 65-80% rock. Using modeling, mapping, and eyewitness videos, they were able to track the ice-to-rock ratio and determine that this landslide was about 80% rock. The ice fell approximately 3400 feet, which gave it just the right amount of potential energy to liquidize the ice and get enough water to cause the flood. They'd found it.

With this frantic around-the-clock science, they were able to discover the source of the flood and monitor the ongoing danger to prevent further disaster. That being said, this was still a huge catastrophe. Two hydropower plants were completely wiped out, leaving 204 people missing or dead. Every bridge going into Raini was destroyed, cutting them off from supplies. Furthermore, muck was carried downstream and would affect the clean water in Delhi and other population centers for the next three years.

Raini is now at the center of an ongoing debate. We need clean energy to slow glacier melt, but increased development means increased exposure to hazards. The villagers in Raini had voiced concerns about the two hydropower plants, saying that they were dumping muck along the river, which increased chances of water pollution. Furthermore, they brought up the lack of safety measures to warn workers in case of emergency. All of their concerns were largely ignored until it was too late.

Rupper concluded by posing the question: how do we best balance conservation and development? There are no easy answers, and it is up to the rising generation of geologists to continue fighting for our planet whilst remembering to protect individuals.