A rapidly expanding dammed lake above a Nepal-Tibet flood zone poses a severe new threat to Gyirong Port, where hundreds of people remain unaccounted for following an initial catastrophic surge.
Formed by mudslides near the junction of two rivers, the blockage sits about 11 miles upstream of Rasuwagadhi and has created a 27-acre lake, according to Nepal's National Disaster Risk Reduction and Management Authority (NDRRMA). China's Ministry of Water Resources estimated on Aug. 27 that the lake currently holds roughly 2 million cubic meters (528 million gallons) of water. Fueled by incoming rain, it is expected to absorb another 3 million cubic meters (793 million gallons) over the next three days.
The situation is increasingly precarious. The ministry warned that the lake is already overflowing and faces a high risk of a sudden release that could once again inundate Gyirong Port and communities downstream. Drone reconnaissance conducted by fire and rescue personnel - and reported by the state-run Xinhua News Agency on Aug. 27 - confirmed the danger, revealing that the lake's surface continues to expand with water levels visibly higher than the day before.
In response to the mounting threat, Nepalese authorities have urged all residents, travelers, and rescue personnel along the Bhote Koshi River corridor to completely avoid riverbanks and other high-risk zones.
This secondary crisis emerges as the toll from the first flood continues to rise.
An Aug. 27 update from the NDRRMA confirmed that 359 bodies have been recovered in Nepal, with another 910 individuals still out of contact. Meanwhile, across the border, the Gyirong disaster command reported three confirmed deaths and 558 people missing in Tibet - including 260 foreign nationals - as of 8 a.m. on Aug. 27.
As the Epoch Times notes, the new lake is still rising...
The new lake formed in debris left by the disaster near the confluence of the Cuojian River and Purepuqiang Zangbo, upstream of Gyirong Port.
Chinese authorities on Aug. 27 found that the broader landslide area had not expanded, but the lake surface continued to grow.
Water was already passing over the natural barrier rather than remaining contained behind it. Authorities described the condition as overflowing, not a full breach.
Natural dams are formed suddenly from loose rock, soil, and other debris rather than engineered materials.
According to National Cheng Kung University resource-engineering professor Huang Jing-sheng, water penetrating such debris can increase internal water pressure and reduce the friction helping hold the blockage together.
Historical records compiled by Taiwan's Agriculture Ministry identify erosion from water flowing over the top as one common failure mechanism for natural dams.
The agency cautions that historical cases cannot predict how a particular lake will behave.
New Hazard Complicates Access
The dammed lake sits above an area already heavily damaged by the first flood.
The edge of the debris flow was located about 1.6 miles from Gyirong Port, with deposits approaching 5 feet thick in places, Xinhua reported.
An engineering team was using drones and 3D laser scanners to survey the blockage and measure its shape, surrounding rock, and water flow, according to Chinese rescue authorities, who said the upstream threat had to be addressed before crews could safely clear the large debris field closer to the port.
On the Nepal side, the new danger extends directly into the rescue corridor.
The NDRRMA and Nepal's hydrology authorities urged residents, travelers, and rescue personnel along the lower Bhotekoshi to remain away from riverbanks and other exposed areas.
That warning is tied to the newly formed lake, not the initial flood surge.
More Water Forecast
China's National Meteorological Center continued to forecast additional rainfall around Gyirong through Aug. 29.
Gyirong Port was expected to see light rain overnight on Aug. 27 and into Aug. 28, with moderate rain at times.
Rain was forecast to intensify on Aug. 29, with light to moderate rain and periods of moderate to heavy rain.
Along the corridor from Gyirong Port toward Nepal, the China Meteorological Administration's public weather service forecast moderate to heavy rain on Aug. 27, moderate rain on Aug. 28, and moderate to heavy rain again on Aug. 29, with possible thunderstorms, strong winds, and hail.
A Chinese Water Ministry hydrological assessment put inflow into the lake at about 15 cubic meters per second (4,000 gallons per second) and said the volume was still increasing.
Based on the rainfall forecast, the ministry estimated that the lake could receive another 3 million cubic meters (793 million gallons) of water over the next three days.