Landslide strikes Hongcheon mountain not on any hazard watch list; no casualties

A landslide has struck a mountain not included among the thousands of sites flagged as landslide-risk areas, raising fresh concerns about the limits of existing hazard monitoring.

At around 7:49 a.m. Friday, a landslide struck Sutsan in Mogok-ri, Seo-myeon, Hongcheon-gun, Gangwon Province, prompting 16 residents to evacuate to a nearby community center.

No casualties were reported. One storage shed used to house farm equipment was buried, and part of the surrounding farmland was damaged.

Authorities deployed 10 pieces of heavy equipment and 22 personnel to control the scene and carry out safety measures.

Officials estimate that soil and rocks broke loose from around 90 percent of the way up the mountain — near the 320-meter summit — and slid roughly 20 to 30 meters down the slope.

The site was not among the 3,234 landslide-risk areas managed by Gangwon Province. Authorities also confirmed that no separate construction work had been under way and no solar power facilities had been installed on the mountain.

According to the Gangwon Regional Office of the Korea Meteorological Administration, 45.8 millimeters of rain fell over three days from Monday through Wednesday.

Residents said small rocks had been rolling down the mountain intermittently for three days before the landslide, and that on Thursday rockfall continued throughout the day — an unusual occurrence, they said.

Hongcheon-gun said it plans to determine when residents can return after verifying conditions at the site, and has requested technical advice from the Korea Forest Disaster Safety Technology Institute to quickly identify the precise cause, the extent of damage and the direction of future recovery efforts.

The county said ongoing soil runoff makes immediate restoration work difficult, and that emergency measures — including debris removal and tarpaulin installation — will begin as soon as the flow stops.

A full investigation by specialist agencies will then determine the exact cause of the landslide and the scope of damage, after which the county will pursue the necessary restoration work.