Heavy rainfall has triggered flash floods and overflow from Nan river in several districts of Nan province have inundated homes and rendered several roads impassable.

The Nan Provincial Disaster Prevention and Mitigation Office reported on Wednesday morning that heavy downpour started pounding the northern province at about 8am, triggering runoff from forested areas and rivers to overflow. Many residential areas in Pua districts were inundated.

Affected areas included villages Moo 2, 8 and 10 in tambon Ouan; villages Moo 3, 6 and 7 in tambon Woranakhon; villages Moo 1 and 5 in tambon Sila Laeng; villages Moo 2 in tambon Chai Wattana; and villages Moo 1,4,7, and 8 in tambon Pua.

Floodwaters have entered many houses, while several roads are impassable because of flooding and landslides.

High waters were also reported in village Moo 11 in tambon Fai Kaeo of Phu Phiang district, village Moo 4 in tambon Muang Chang and village Moo 1 in tambon Phong of Santisuk district.

Authorities are helping local residents to evacuate from flood-hit areas and conducting preliminary damage assessments.

Earlier on Wednesday morning, the Department of Disaster Prevention and Mitigation issued a Cell Broadcast warning for flooding in Pua district, urging residents to immediately move their belongings to higher ground.

The Nan Highway Office 2 reported several roads were flooded, causing traffic to halt on Highway 101 between Chang Phueak and Pua intersection, Highway 1371 between Teentok and Ban Mon area near Ban Fai bridge and Highway 1256 in areas between Pua and Doi Phu Kha National Park, where a bridge collapsed.

Officials have installed warning signs and safety equipment and advised motorists to avoid the affected routes.

The Northern Meteorological Centre issued a weather advisory at 7am, reporting that light to moderate rain covering all districts of Nan and nearby provinces including Phrae, Phayao, Lampang, Lamphun and Chiang Rai.

The rain moved southwest and locals were told to exercise caution while driving due to slippery road conditions and reduced visibility.

People living in low-lying areas and foothill communities were also advised to closely monitor rainfall levels, as continued precipitation could lead to further flooding and flash floods.