A hiker clung to clumps of grass during a storm on a mountain.

The mountaineers took the one-hour trek to Doi Ma Muang Sam Muen peak to see the Pre Toh Lor Su waterfall when a thunderstorm battered them along the trail in Tak province, Thailand, on August 12.

Footage shows one of the climbers sprawled on the ground and holding onto anything she could while her friends tried to help each other inch their way uphill.

The group arrived at the campsite safely, holding each other across the terrain despite the stormy weather.

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