The blockage of the Kali Gandaki River early Sunday morning was caused by a landslide. But unlike other landslides, which generally are triggered by torrential rain that weakens the soil, this was a dry landslide that came crashing down and blocked the water flow of the river. But what exactly is this dry landslide?
Rishi Ram Sharma, director general at the Department of Hydrology and Meteorology (DHM) said dry landslides are triggered by deep failures of the weakened slopes. “Rain wasn’t the culprit here as the weather was completely dry and there was no rainfall on Friday or Saturday,” said Sharma.
The constant shaking of the land due to the powerful Great Quake of April 25 and its aftershocks destabilised the slope over the Kali Gandaki River. As the aftershocks are still occurring, the loosened mud, boulders and stones ultimately gave way and came crashing down, blocking the river in the wee hours of Sunday morning.
The DHM has also mobilised technical team comprising hydrologists and technical experts to monitor and inspect the dammed lake site at Baisari in Myagdi district. If the team reaches anywhere near the blocked river site, it will try to measure the depth and volume of the water level in the artificial lake. However, Sharma said that reaching the site is the biggest challenge. The loose soil are still falling and the dust cloud formed from the falling debris has severely dampened the visibility in the area.
“We have issued high alert to downstream villages as far as Chitwan and Nawalaparasi about the possible threat of flooding due to the burst of the dammed lake in the Kali Gandaki River and appealed them to remain in safer places,” he said.