Many ancient civilizations have a flood story in their mythology. There is the story of Noah’s Ark in Judeo-Christian countries and Sumerians have the Epic of Gilgamesh. In Hinduism we have the story of Manu.
It is amazing that countries spread so far apart have such similar stories and it does not end there. Another similarity is in the stories of children who were floated in baskets down rivers. Yocheved put her son Moses in a small ark and placed it on the river in which the Pharaoah’s daughter bathed. In Mahabharata, Kunti did a similar thing and sent Karna floating down the river.
The book I am reading The Fourteen Dalai Lamas: A Sacred Legacy of Reincarnation has a similar story about King Nyatri Tsanpo, regarded as Tibet’s first recorded monarch. King Tsanpo was Indian by birth, descended from a Licchavi king. When he was born, he had many unusual signs in his body and hence his father put him in a casket and sent him river rafting down the Ganges. The child was rescued by a farmer, and later when he came to know his trip down the river, he was overcome with grief and fled to the Himalayas. He arrived at the Yarlung valley in Tibet and later became the King.