Nan and Tak face highest flash-flood risk in three-day rain alert
Northern Thailand is on alert for heavy rain from 16-18 July, with parts of Nan and Tak forecast to receive more than 200 millimetres and face severe flash-flood and landslide risks.
Residents across northern Thailand have been warned to prepare for flash floods, landslides and flooding in low-lying areas as heavy to very heavy rain is forecast from July 16 to 18.
The Office of the National Water Resources Region 1, or ONWR Region 1, identified Pua district in Nan and Mae Sot and Phop Phra districts in Tak as the highest-risk areas, with accumulated rainfall expected to exceed 200 millimetres over the three-day period.
The Thai Meteorological Department said rainfall across the country would ease between July 16 and 19, but isolated heavy rain would continue in the North, where thunderstorms were expected across 30-40% of the region.
Tak bears brunt of rain on July 16 and 17
Mae Ramat district in Tak was placed in the orange category for July 16, indicating very heavy rain of more than 90mm.
Areas in the yellow category, where rainfall of 35-90mm was forecast, included Sop Moei in Mae Hong Son; Tha Song Yang and Mae Sot in Tak; Noen Maprang in Phitsanulok; and Mueang Phetchabun and Khao Kho in Phetchabun.
The focus will shift further south in Tak on July 17, when Mae Sot and Phop Phra are expected to receive more than 90mm of rain.
Omkoi in Chiang Mai, Tha Song Yang and Wang Chao in Tak, and Nong Phai in Phetchabun were placed in the yellow category for heavy rain of between 35mm and 90mm.
Risk expands across Nan on 18 July
The area at risk is expected to widen substantially on July 18, with five districts in Nan forecast to receive more than 90mm of rain.
The orange-category districts are Pua, Thung Chang, Chiang Klang, Bo Kluea and Chaloem Phra Kiat.
Heavy rain of between 35mm and 90mm is also forecast in Mae Charim, Na Noi, Tha Wang Pha, Wiang Sa, Santi Suk, Song Khwae and Phu Phiang districts of Nan.
Other yellow-category areas include Chiang Khong, Chiang Saen, Mae Sai and Wiang Kaen in Chiang Rai; Chun, Chiang Kham and Pong in Phayao; Omkoi in Chiang Mai; Mae Sariang in Mae Hong Son; Tha Song Yang in Tak; and Ban Khok in Uttaradit.
Under Thailand’s rainfall classification, daily rainfall of 35.1-90mm is considered heavy, while more than 90mm is classified as very heavy.
Three-day rainfall could exceed 200mm
ONWR Region 1 placed Pua in Nan and Mae Sot and Phop Phra in Tak in its red cumulative-rainfall category, with more than 200mm expected between July 16 and 18.
Thung Chang, Chiang Klang and Bo Kluea districts in Nan were placed in the orange category, with accumulated rainfall forecast at between 150mm and 200mm.
The agency said these areas faced a particularly high risk of landslides and rapid run-off because of the volume of rain expected over a relatively short period.
Residents urged to prepare for flooding
People living on hillsides, near waterways and in low-lying communities have been advised to monitor conditions closely and prepare for sudden flooding.
Residents should move valuable possessions to higher ground and remain alert for rapidly rising water, changes in the colour or speed of streams, and signs of unstable soil around slopes.
The Meteorological Department has similarly warned that heavy and accumulated rainfall can trigger flash floods, forest run-off and overflowing waterways, particularly near foothills and in low-lying areas. Real-time rainfall and water information is available through the national water-data platform.
