Xinhua News Agency reported that the snowslide occurred at the exit of a highway tunnel leading from it Nyingchi town in Medog County to Mainling County in southeastern Tibet.
Municipal officials in Nyingchi, at 3,040 meters (about 10,000 feet) above sea level, said the avalanche trapped people in their vehicles and a rescue operation was underway for the missing, Xinhua reported.
It is not clear how many people may be missing from the incident, which took place Tuesday night.
China’s Ministry of Emergency Management sent a disaster response team to Tibet on Wednesday, calling for large-scale rescue efforts and an assessment of how many people are still stranded, according to China’s Global Times newspaper.
Avalanches are not uncommon in the Himalayas. Last October, at least 26 people were killed when a mountaineering expedition was caught in an avalanche on Mount Draupadi ka Danda-II in India’s northern state of Uttarakhand.