In the days since Tsering Gelbu Lama’s wife was swept away by devastating floods along the Nepal-Tibet border, he still hasn't told his 4-year-old daughter that her mother is dead.

Lama wiped away tears as he sat on the floor of a Buddhist monastery turned makeshift shelter for hundreds of others evacuated from remote villages to the capital, Kathmandu.

“I don’t know how I will pass on our culture to her,” he said as he coaxed a spoonful of rice into her mouth.

For Lama and a rising number of others displaced by the floods, the losses go beyond homes and belongings. Communities whose culture and practices, often tied to ancestral land, are eroding as young people leave for the city now worry if their sacred traditions can be preserved.

“We’ve become homeless not only because we’ve lost our land — we’ve become homeless with our culture and tradition,&rdq...