KATHMANDU, Aug 26: The massive flood that swept through Rasuwa was unlikely to have been caused by rainfall in the district, preliminary analysis by the Meteorological Forecasting Division shows, raising the possibility of a glacial lake outburst or dam breach on the Tibetan side.
According to meteorologist Sanjib Adhikari, there has been no significant rainfall in Rasuwa over the past 24 hours.
He said some parts of Sindhupalchok received heavy to very heavy rainfall during the period, while most areas of Rasuwa recorded only light to moderate rainfall. The Thambuchet station in Rasuwa recorded around 7 mm of rainfall, he said.
Flood in Rasuwa caused by glacial lake outburst
Data from the past 12 hours also show that rainfall in Sindhupalchok has decreased, while Rasuwa has not received any significant additional rainfall, Adhikari said. Given this situation, the preliminary analysis suggests that the massive flood in Rasuwa was not caused by local rainfall.
Analysis of satellite images showed dense cloud cover over Dolakha, Sindhupalchok and the Tibetan region, while comparatively less cloud cover was observed over Rasuwa and surrounding areas, Adhikari said.
Based on this, authorities have preliminarily suspected that a glacial lake outburst or dam breach may have occurred on the Tibetan side, triggering the flood in Rasuwa. However, the actual cause of the flood is still being investigated, and a detailed report will be made public later, the division said.
Adhikari said the flood has now moved downstream from Rasuwa toward Nuwakot, Dhading and Chitwan. He urged people living along riverbanks to move to safer locations.
He also warned that the rising water level in the major river could increase water levels in smaller rivers and streams that flow into it. Residents in those areas have also been urged to exercise extra caution.
Meanwhile, the immediate weather conditions appear relatively favorable for rescue and response operations, according to the division. Adhikari said there is no likelihood of heavy rainfall in the affected areas over the next three to four hours and that cloud cover is not particularly dense.
This is expected to minimize weather-related disruptions to rescue and relief operations in the immediate term. The division said the National Disaster Risk Reduction and Management Authority and other agencies involved in the response could use this window for rescue and relief operations.
However, Adhikari said some mountainous and hilly areas of Bagmati Province could receive heavy rainfall from this evening through the night and into tomorrow. Residents in affected areas have therefore been urged to closely follow weather and flood alerts and avoid going near rivers and streams in risky areas.
