Hundreds of thousands still at risk of climate-linked floods in Nepal

Long before a wave of water rushed down the Bhote Koshi river and its tributaries, researchers were working to calculate just how many people are living downstream and exposed to potentially catastrophic flood risk in the areas that drain from Nepal’s high mountain basins.The number they came up with — about 294,000 and growing — shows just how many people are living in areas of extreme risk in a country where climate change is destabilizing the rock and ice holding Himalayan slopes together and where meltwater is pooling in an ever-growing catalog of glacial lakes.“For Nepal, it shows that there’s a lot of development going on very close to the river channel in these potentially hazardous zones,” said Scott Watson, a senior research fellow at the University of Leeds in England who studies glacial lakes.“That’s driven by tourism and the trade routes.

The recent disaster was on the main trade route between Nepal and the Tibetan plateau.”The August disaster — when a massive rock and ice avalanche plunged off the an almost 24,000-foot peak called Langtang Lirung and caused a debris flow that traveled more about 120 miles — killed at least 1,455 people, and at least 5,285 people are still missing, according to Nepali authorities.Nearly 14,000 people were rescued.If nothing is done, researchers say the number of people exposed will only grow.

“Hopefully, for Nepal, it’s kind of a bit of a wake-up call, this unfortunate recent disaster, in that there needs to be obviously a lot more focus on thinking about early warning systems, but also land use zoning,” Watson said.“We show that there’s a lot of buildings, there’s a lot of people very close to the river channel that are exposed to these hazards.”About 108,000 of those people are downstream of glacial lakes, the researchers found.

Many of those glacial lakes are pools of water dammed by ice that could fail and release a flush of water all at once.The researchers started putting toge...