A dam broke following heavy rain, sending torrents of water downstream in Thailand.

Residents in the northern region of Lampang province were urged to evacuate after two dams overflowed.

Officials said the Kiew Kho Ma Dam and Kiew Lom Dam burst their banks on September 25 due to continuous rainfall. The upper area of Lampang province has been experiencing flash floods since Monday, causing water levels to rise in the dams.

The Kiew Kho Ma Dam held 189 million cubic metres of water, exceeding its capacity by 111 per cent. This led irrigation officers to discharge water at 257 cubic metres per second.

They said that if further rainfall occurs downstream, the water level of the Wang River is expected to rise, potentially impacting 13 villages in the Jaehom district.

The discharged water from the Kiew Kho Ma Dam would flow to the Kiew Lom Dam, which would also experience increased water levels.

On Wednesday, Kiew Lom Dam held 88 million cubic metres or 83 per cent of its capacity. Officials began discharging water into the Wang River at a rate of 320 cubic metres per second at 1 am.

As a result, the Wang River's level in the Mueang district has risen by over 11.8 inches (30 centimetres) and could reach 33.5 inches (85 centimetres).

Lampang City Municipality has increased its alert level to prepare for the rising water, which could potentially reach critical overflow levels if heavy rains and flash floods continue.

Residents in low-lying areas are advised to move valuables and essential items to higher ground.

To assist those affected, the municipality has established a command centre.

Thailand and neighbouring countries in Southeast Asia are at the start of their annual monsoon rainy season which sees soaring temperatures followed by powerful rain storms. The rudimentary infrastructure often struggles with the deluge, leading to widespread flash floods.