A waterfall viewing platform collapsed in a flash flood in Thailand.

Footage shows raging currents ripping through the Umphang Wildlife Sanctuary in Tak province on September 21.

Park officials have temporarily closed the Thi Lo Su Waterfall area, where the torrents destroyed a concrete viewing platform. Mud, branches, and fallen trees also littered the trail.

Authorities said a 15.5-mile stretch from the park's ticketing area to the camping grounds was covered in mud.

The Thai Meteorological Department (TMD) on September 21 said northern Thailand, including Tak province, would experience widespread thundershowers and isolated heavy to very heavy rains.

Thailand and neighbouring countries in Southeast Asia are in their annual monsoon rainy season which sees soaring temperatures followed by powerful rain storms in the afternoon leading to widespread flash floods.