Kathmandu: A powerful flash flood along Nepal’s Bhote Koshi-Trishuli-Narayani river system has caused widespread destruction, burying parts of towns and villages under mud and debris and washing away roads, bridges and embankments.
The swollen Bhote Koshi River swept into Nepal’s Rasuwa district from Tibet on Wednesday, sending huge volumes of water and debris downstream and severely affecting communities along its banks.
Satellite images show scale of devastation
High-resolution satellite images shared by space analytics firm Suhora have revealed the extent of the destruction in Trishuli market, Betrawati town and Tupche village in Nuwakot.
The images show large parts of Trishuli market covered in mud and slush. Several structures that once stood away from the river were also found buried beneath layers of debris following the flood.
In Betrawati, the commercial centre has reportedly been covered by mud, boulders and debris, while bridges have been swept away, leaving the area difficult to access.
Roads and power infrastructure badly affected
The flooding has severely damaged connectivity in the region. Nepal’s Roads Department said the 42-kilometre road linking Betrawati with the border town of Rasuwa was completely destroyed.
Concrete bridges at several locations were also swept away. Power lines and substations have suffered damage, disrupting essential services and communications in affected areas.
Barrier lake creates another concern
Rescue and relief operations have been complicated by the formation of a barrier lake following the flash flood.
Early indications suggest that a glacial lake outburst upstream in Tibet may have triggered the initial surge. The resulting debris and slush then appear to have blocked the river, creating the barrier lake.
Risk of another flash flood remains
China’s Ministry of Water Resources has warned that the barrier lake has begun overflowing and faces a high risk of breaching over the next three days.
A breach could release millions of cubic metres of accumulated water downstream, potentially triggering another flash flood and putting already affected communities at further risk.
Authorities and rescue teams are continuing to deal with damaged infrastructure, unstable conditions and difficult access as efforts to assist stranded people continue.