The pre-dawn landslide hit in Zhenxiong County, Yunnan province, state news agency Xinhua reported, citing local authorities.
State broadcaster CCTV said around 18 households were buried, and that more than 200 people were “urgently evacuated” from the area.
Authorities have launched an emergency response involving over 200 rescue workers as well as dozens of fire engines and other equipment, according to CCTV.
Two people had been found dead at the site as of 1:30 pm local time (0530 GMT), CCTV said, citing a reporter on the scene.
One local told the state-run Beijing News outlet that she was asleep when the disaster hit and that parts of her ceiling had fallen onto her head.
“At the time I thought it was an earthquake, but later I knew it was the hillslope collapsing,” another resident told the outlet.
Both were quoted under pseudonyms.
Footage shared on social media by a local broadcaster showed emergency workers in orange jumpsuits and helmets forming ranks outside a fire station as snowflakes whirled through the air.
Other images showed rescuers picking through towering piles of collapsed masonry in which a few personal belongings could be seen.
Chinese President Xi Jinping urged “all-out” rescue efforts, CCTV reported.
Xi “demanded that rescue forces are organized quickly… and efforts made to reduce casualties as far as possible,” the broadcaster reported him as saying.
He added that it was “necessary to properly handle the work of comforting the families of the deceased and resettling affected people”.
CCTV broadcast an image it said showed a firefighter working to pull a trapped villager from inside a home affected by the disaster.
The local village head declined to speak about the landslide when contacted by phone, telling AFP he was “too busy”.
Landslides are common in Yunnan, a far-flung and largely impoverished region of China where steep mountain ranges butt against the Himalayan plateau.
Monday’s disaster occurred in a rural area surrounded by towering peaks dusted with snow, state media footage showed.
Temperatures in Zhenxiong hovered at around minus four degrees Celsius (24.8 degrees Fahrenheit) on Monday morning, weather data showed.
There was no immediate official explanation for what may have caused the landslide, which struck at 5:51 am (2151 GMT Sunday).
Efforts to establish what happened are underway, Xinhua reported.
China has experienced a string of natural disasters in recent months, some following extreme weather events such as sudden, heavy downpours.
In September, rainstorms in the southern region of Guangxi triggered a mountain landslide that killed at least seven people, according to media reports.
Heavy rains sparked a similar disaster near the northern city of Xi’an in August, causing the deaths of more than 20 people.
And in June, a landslide in southwestern Sichuan province — also remote and mountainous — killed 19 people.