The death toll from a landslide in China’s Yunnan province rose to 11 on Tuesday as rescue workers battled freezing temperatures and snow to locate dozens of missing people.

Rescuers worked through the night sifting deep mounds of earth at the site of the landslide in Zhenxiong County, state-owned China Central Television (CCTV) reported on Tuesday.

One rescuer said large machines cannot be used due to the unstable soil, according to a report from local media outlet The Cover, owned by the Sichuan Daily Newspaper Press Group.

“If the excavation is unloaded below, the top may continue to collapse. It is difficult to carry out large-scale mechanical operations, and it is very difficult to rescue on site,” the worker was quoted as saying in the report.

After the landslide hit on Monday, at least 47 people from 18 households were reported missing, CCTV said. Eight of the missing were found dead on Monday afternoon, according to Zhaotong Daily, a local state-owned media outlet.

Another two people were hospitalized for head and body injuries, the national health commission said.

The landslide hit two villages in the southwestern city of Zhaotong at about 5:51am (2151 GMT), covering houses in brown mountain soil at the foot of a hill, CCTV reported.

“The mountain just collapsed, dozens were buried,” a man surnamed Gu, who witnessed the landslide, told the state-owned TV station for the neighbouring province of Guizhou. Gu said four of his relatives were buried under the rubble.

“They were all sleeping in their homes,” he said.

More than 500 people were evacuated from their homes, CCTV said.

Officials told a press conference on Tuesday the landslide was triggered at a steep cliff area at the top of a mountain slope.