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The death toll continues to rise after flash flooding hit the border between Nepal and Chinese-administered Tibet. The flood carried away villages in minutes and killed hundreds. The region is no stranger to this kind of tragedy. People there have endured other disasters, including a deadly earthquake in 2015 that took thousands of lives. NPR's Katia Riddle brings us this report on what makes the country's geography so uniquely prone to these kinds of events.
KATIA RIDDLE, BYLINE: Nepal has long been a place for Hindu and Buddhist pilgrims, as well as a destination for international tourists. But there's another group of people who have, for decades, been engaged in an ongoing love affair with this unique corner of the world - scientists.
MIKE SEARLE: Nepal - the Himalayas are a spectacularly good place to work.
RIDDLE: Mike Searle is a retired professor of earth sciences at University of Oxford. He's been traveling to this region to study it for 40 years.
SEARLE: Well, it is the mecca if you're interested in how you make mountain belts.
RIDDLE: There's no other place like this, he says, where you can see a relatively young mountain range made from some of the most ancient rocks on the Earth. That's because the Himalayan mountains sit at the collision zone between two enormous tectonic plates, the Indian plate and the Eurasian plate.
SEARLE: It's this convergence, north-south convergence, that keeps the Himalaya rising.
RIDDLE: Searle says, not only does this create a unique opportunity for studying plate tectonics and geology, the landscape is spectacular.
SEARLE: You've got this forested lowland. So when you go in the spring, the mountains are just a mass of red, pink and white rhododendrons. Then the high snowcap peaks above that - it's beautiful.
RIDDLE: Beautiful but dangerous due to the risk of landslides. These tall mountains are also home to glaciers, which are melting faster with climate change.
SEARLE: So it seems now that it's pretty certain that the disaster in Nepal happened because of a glacial collapse and a massive great landslide. We don't think it was caused by an earthquake.
RIDDLE: Not caused by an earthquake, but collapsing ice from the glacier did shake the ground in a similar way to an earthquake. That's according to Goran Ekstrom, a seismologist at Columbia University.
GORAN EKSTROM: It's similar in terms of the seismic waves that it makes to a magnitude 5.7 earthquake.
RIDDLE: Ekstrom says, these kinds of events are not unusual in the region. What is unprecedented is how big this one was, swallowing buildings in seconds.
EKSTROM: That size landslide event, we haven't really seen more than once or twice in the last decade or two.
RIDDLE: The forces that made this event to happen, he says, are far greater than anything humans can control. But there is more that could be done to predict these landslides using seismic sensors strategically placed in the region. These sensors could then detect these events as soon as they begin and trigger alarms.
EKSTROM: Then in the case of flooding, you do have minutes - sometimes tens of minutes - of possible time before the flooding actually impacts vulnerable areas.
RIDDLE: The U.S. and other countries have early warning systems in place to detect things like earthquakes and tsunamis. In Nepal, says Ekstrom, these warnings wouldn't stop the destruction, but they could give people enough time to evacuate.
EKSTROM: You can't protect the infrastructure, but you can save lots of lives.
RIDDLE: Nepal has invested substantially in building these kinds of systems, but the country can't do it alone. It would take collaboration and investment from international partners, he says, to help prevent another tragedy. Katia Riddle, NPR News.
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