Engineers Clear Gyirong Mudslide Debris as 100,000-Sq-Meter Lake Holds Stable

Q: What hidden danger in the melting Himalayas triggered a catastrophic flood that left hundreds dead and over a thousand missing?

The hidden danger was a high-altitude glacier collapse — an ice-and-rock avalanche in the melting Himalayas that slammed into the Lhende Khola headwaters, briefly dammed the river, and then unleashed a catastrophic flood downstream. Investigators and satellite analysts say the lower part of a glacier near the Nepal-Tibet border broke away at roughly 5,200 metres and plunged onto the valley floor, generating a debris flow strong enough to register as a seismic event. The US Geological Survey later said the shaking initially mistaken for an earthquake was actually caused by the collapse itself. The collapse appears to have blocked the river temporarily, forming a short-lived lake behind debris. When that natural dam failed, a surge of water, mud, rock and ice raced into the Bhote Koshi and Trishuli river system, destroying bridges, roads, hydropower sites, homes and border facilities. Scientists say the deeper risk lies in rapid warming across the Himalayas. Melting glaciers and thawing permafrost are weakening steep mountain slopes and making glacier tongues, rock faces and ice masses less stable. Experts caution it is too early to attribute this single event entirely to climate change, but they say warming is increasing the likelihood of such cascading disasters — glacier collapses, landslide dams and sudden outburst floods — across the region.

3 articles · Updated · South China Morning Post · Aug 29

Excavators and heavy earth-moving machinery began clearing mud and debris on Saturday to reopen the route to the destroyed Gyirong border checkpoint in Tibet.
An eight-firefighter advance team had retreated Friday night over fears a nearby lake could burst its banks, but the roughly 100,000-square-meter lake remained stable on Saturday.
Radars and drones are monitoring the lake as rescue and clearance work continues around the China-Nepal border crossing under flood and collapse risks.
CCTV said many frontline workers had also joined last July's rescue operation in the same region, where a mudslide washed away a bridge.