Landslide blocks Hongu Khola River in Solukhumbu, raises downstream flood risk, Nepal

The landslide occurred at approximately 07:00 NPT (01:15 UTC), about 100 m (330 feet) below the head office of the Gaurishankar Hydropower project, according to Solukhumbu District Police chief DSP Nabinraja Budhathoki.

Budhathoki estimated that the landslide debris formed an obstruction approximately 35 m (115 feet) high and that the resulting impoundment extended about 100 m (330 feet) along the river, with the accumulated water estimated at approximately 15 m (49 feet) deep.

Water was subsequently reported to be flowing slowly over the debris barrier. Budhathoki said the situation had become less immediately threatening as water escaped over the obstruction, although the possibility of a sudden failure and downstream flooding had not been eliminated.

Initial information relayed by Nepal’s Flood Forecasting Division from the Solukhumbu District Administration Office said additional landsliding was continuing at 08:40 NPT (02:55 UTC). Assistant Chief District Officer Devendra Subedi subsequently told Thaha Khabar that the slope movement had stopped by the time of its report, published at 10:41 NPT (04:56 UTC).

Subedi estimated that the temporary lake was more than 100 m (330 feet) long and 40–50 m (130–165 feet) deep. Chief District Officer Kaman Singh Thapa Magar described a debris barrier approximately 16 m (52 feet) high and about 100 m (330 feet) across.

The Flood Forecasting Division advised residents along Hongu Khola, the Dudh Koshi and surrounding riverbank areas to remain highly vigilant until further notice.

Thapa Magar said residents had been advised to move toward safer locations and that district authorities in Khotang and Okhaldhunga had been notified because Hongu Khola drains into the Dudh Koshi. No formal evacuation order was identified in the available reports.

Police said a sudden release could affect downstream areas of Sotang and Thulung Dudhkoshi rural municipalities before reaching sections of the Dudh Koshi in Khotang and Okhaldhunga districts.

Authorities also alerted nearby hydropower operations, including Gaurishankar Hydropower, Dudh Koshi Hydropower Nepal, and two projects operated by Sahas Urja. Workers and vehicles in potentially exposed areas were instructed to move toward safer locations.

Mahakulung Rural Municipality chair Surya Bahadur Kulung said the local government had dispatched an excavator toward the site and was assessing measures to manage the obstruction and reduce downstream risk. Available reports do not confirm that the excavator had reached the blockage or begun removing debris.

Reports differ on the exact ward boundary at the site, variously placing it between wards 2 and 4 or wards 4 and 5. All the reports identify the blockage as being near Gudel in Mahakulung Rural Municipality. The river’s name is also transliterated as Hongu, Hunga and Hunku in different sources.

The Hongu Khola landslide occurred just 16 days after the catastrophic August 26 Bhote Koshi–Trishuli flood disaster in northern Nepal, which followed a major collapse of ice, rock and sediment in the high Himalayas.

As of September 9, at least 1 380 people had been confirmed dead and around 5 500 remained missing, while search and recovery operations were continuing across affected areas. The disaster caused extensive damage in Rasuwa, Nuwakot, Dhading and other districts along the Bhote Koshi and Trishuli river systems.

References:

¹ Hunga River partially reopens; residents urged to maintain high alertness – Nagarik News – September 11, 2026

² Landslide blocks Hongu Khola as authorities warn downstream districts – Prasashan – September 11, 2026