The avalanche swept the family along with houses at around five in the evening, informed Humla District Police Office. Hilsa Border police post has also suffered damage.
Police have identified the missing mother as 40 years old Kema Lama of Simikot-8 while the names of her children remains unknown.
The avalanche occured at Naumule of Muchu VDC, which is 33 km away from the district headquarters Simikot, informed Humla Chief District Officer, Bijaya Narayan Manandhar.
"Even though we have deployed security personnel at the site for rescue, the missing are still nowhere in sight," said Manandhar. He also said rescuers have been shifting those at risk to safer grounds.
Manandhar informed that around eight houses are buried under the avalanche and recue has been very difficult due to continuous rainfall.
Mugu avalanche update: Rescue team fail to reach avalanche site