Man Kumar Limbu (25), Pengkit Limbu (23) and their 7-year-old child Anish Limbu were sleeping when boulders rolled over their hutment during heavy rains.
The hutment, falling in Lodhoma Gram Panchayat 2 on a steep hilly slope, is above Nippon Micro Hydro Project near Basbotay on the way to Mishima.
The bodies have been sent for post-mortem.