A landslide that may have blocked a tributary is a possible cause of flash flooding in the Budhi Gandaki river, the Department of Hydrology and Meteorology’s Flood Forecasting Section said on Sunday.

Binod Parajuli, a hydrologist at the section, said satellite images showed a large landslide near Chumchet in Chumnubri Rural Municipality, Gorkha district. The landslide is believed to have occurred on Saturday. “We are examining satellite images. A large landslide is visible around Chumchet. It appears to have occurred yesterday. The flooding may have been triggered when a blocked tributary of the Budhi Gandaki suddenly released water,” Parajuli told Kantipur.

Residents have suggested that an avalanche may have occurred on Mount Shringi, but this has not been confirmed. Parajuli said a landslide had occurred near the mountain, adding that all explanations remained preliminary. Authorities suspect that a landslide blocked the Ungeling tributary of the Budhi Gandaki.

The river’s flow continues to fluctuate, the section said. With water levels above the danger threshold and continuing to rise and fall, the Trishuli river corridor as far downstream as Benighat remains at very high risk of flooding.

Authorities have also urged people living along the riverbanks around Mugling and farther downstream in Chitwan and Nawalparasi districts to remain alert.