A video showing the participants lined up along the stream and performing the ritual has attracted millions of views in recent days.
The footage was recorded during the Golden Harvest Festival, held from September 25 to 27 in Binh Lu Commune.
One of the festival's highlights was the 'Ap Ho Chieng' hair-washing ritual along the Nam Pe Stream, a tradition associated with washing away misfortune and praying for health and good fortune.
Nearly 100 White Thai participants entered the stream in a long line, each carrying a basin of water to perform the ritual under the guidance of a traditional ritual practitioner.
They lowered their long hair into the stream before sweeping it backwards one by one to the sound of gongs.
According to the Binh Lu Commune People's Committee, the ritual was recreated alongside a water-splashing ceremony for good luck.
It was among several traditional cultural activities featured at this year's festival, alongside a Giay wedding ceremony, a Thai new-rice celebration and cultural performances.
Tran Nhu Hop, vice chairman of the Binh Lu Commune People's Committee, said this year's festival featured cultural spaces representing ethnic communities living in the area, with traditional customs and rituals recreated for residents and visitors.
Most of those taking part in the hair-washing ritual were students under 18 from local schools.
The commune hopes to make the festival an annual event to promote Binh Lu and tourism in Lai Chau Province.
Located along the Nam Pe Stream, Binh Lu is known for its rice fields and diverse ethnic cultures. The festival is held during the ripening rice season as part of efforts to attract more visitors to the area.
