Footage shows a row of the Tsunami-like roll clouds towering over homes after rain in Thailand on May 8.
The weather phenomenon was seen above the Pakkret district of Nonthaburi province near the capital Bangkok shortly after an early evening storm.
Onlooker Apunwatree Yong said: ‘They looked like a dark mountain in the sky. It was quite scary.’
A roll cloud is a low, horizontal, tube-shaped cloud formation, that resembles a large tidal wave. They form when a downdraft from an advancing storm causes moist warm air to rise, cool below its dew point and form a cloud. When this happens uniformly along an extended front, a roll cloud may form.
Thailand and other countries in Southeast Asia such as Malaysia and Indonesia are approaching their tropical monsoon rainy season. Soaring temperatures reaching 35 degrees Celsius are often followed by powerful tropical storms with thunder, lightning, rain and flash floods.