The predawn landslide buried 18 homes when it hit Zhenxiong county, in Yunnan province, on Monday.
More than 24 hours after the disaster, state news agency Xinhua reported that rescue workers were in a “race against time” on Tuesday to find those still missing, after a night of subzero temperatures.
Yunnan is among several provinces in China currently experiencing bitterly cold temperatures, according to the National Meteorological Centre.
“Search and rescue efforts persisted through the night,” firefighter Li Shenglong told Xinhua.
Two hundred emergency workers, including soldiers, were dispatched to the scene – a rural area surrounded by towering peaks dusted with snow – along with dozens of fire engines and other equipment.
The area is covered in thick snow and rescuers were “using all kinds of tools to search for survivors” amid the debris, Xinhua reported.
Wu Junyao, the director of the natural resources and planning bureau of Zhaotong, which includes the affected villages, said the disaster “resulted from a collapse in the steep cliff area atop the slope”.
Chinese President Xi Jinping has ordered “all-out” rescue efforts.
Landslides are common in Yunnan, a far-flung region where steep mountain ranges abut the Himalayan plateau.
China has experienced a string of natural disasters in recent months, some following extreme weather events such as sudden, heavy downpours.
Rainstorms last September in the southern region of Guangxi triggered a mountain landslide that killed at least seven people, according to media reports.
In August, heavy rains sparked a similar disaster near the northern city of Xi’an, killing more than 20 people.