This is the dramatic moment a carpark roof collapsed damaging dozens of cars during a raging monsoon storm in Thailand.

CCTV footage shows fierce winds and rain battering the Chaiyaphum Hospital parking lot in Chaiyaphum province on May 23.

As the rainstorm pummeled the area, a whirlwind blew down the structure, which fell on 15 cars, including newly bought sedans and trucks. The vehicles were dented or had shattered windows and windscreens.

There were no injuries as the cars were all vacant at the time.

Hospital director Dr. Narongsak Bamrungthin said the roof would cost 7 million THB (202.8k USD) to repair. He said: 'The owners will be compensated for the damage. We also helped them retrieve their cars under the collapsed roof.'

Car owner Tawatchai, 45, said he had parked his white Mazda pick-up truck to visit a relative when the storm struck.

He said: 'I could not go outside to check since the wind was so strong. After it subsided, I discovered that my truck under the destroyed roof. It had been blown by the storm from my parking spot.'

The Thailand Meteorological Agency declared the start of the rainy season on Monday, May 22.

The period sees soaring temperatures followed by powerful rain storms in the afternoon leading to widespread flash floods.