Thailand reports 6 landslide and flood incidents on Sept 20

Thailand’s Department of Mineral Resources (DMR) reported four landslides and two flash floods across Phetchabun, Surat Thani, Mae Hong Son and Chiang Mai in its 9.30am update on Sunday (September 20, 2026). The incidents affected roads, bridges, farmland and routes into and out of villages.

Mae Hong Son and Chiang Mai each experienced both landslides and flash floods, accounting for DMR’s total of six incidents across four provinces.

DMR is monitoring 31 provinces for landslide and flash-flood risks, with 27 covered by a specific alert for September 19–21, 2026.

Phetchabun landslide blocks one lane of Highway 12

Soil and rocks blocked one lane of Highway 12 in Phetchabun on September 19, according to DMR. The landslide was reported at kilometre marker 373+400 on the Nam Duk–Huai Sam Makhao section, in Nam Phu subdistrict, Chon Daen district.

Local officials and agencies in Phetchabun inspected the site and provided assistance to residents.

Surat Thani landslide severs road in Phanom

In Surat Thani’s Phanom district, a landslide affecting Ban Saphan Tao and Ban Khlong Phum Duang in Khlong Sok subdistrict severed a road, leaving it impassable.

Local officials and agencies in Surat Thani inspected the affected areas and assisted residents.

Mae Hong Son road blocked amid risk of further slides

A landslide and flash flooding in Mae Hong Son caused soil to slide onto Rural Road MS 3007 between Ban Mae Sape Tai and Ban Mae Sape Nuea in Khun Yuam subdistrict, Khun Yuam district.

Local agencies in Mae Hong Son inspected the area and provided assistance. Continued rainfall remained a concern because it could trigger further movement of soil on steep slopes.

Chiang Mai floods damage two bridge approaches

Landslides and flash floods damaged two bridge approaches and flooded farmland in Chiang Mai’s Wiang Haeng district, according to DMR. Several villages in Saen Hai, Mueang Haeng and Piang Luang subdistricts were affected.

Damage to transport routes in Wiang Haeng included soil blocking the Mueang Haeng–Pai road and village access roads, leaving some stretches impassable to vehicles. Local officials and agencies inspected the affected areas and assisted residents.

DMR monitors 31 provinces with 27 under specific alert

DMR’s wider monitoring area covers 31 provinces, of which 27 are included in its specific landslide and flash-flood alert for September 19–21, 2026. The full monitoring list comprises:

• North — 11 provinces: Mae Hong Son, Chiang Mai, Lampang, Tak, Nan, Phrae, Uttaradit, Phetchabun, Phitsanulok, Kamphaeng Phet and Sukhothai.
• Central region — two provinces: Nakhon Nayok and Saraburi.
• Northeast — five provinces: Loei, Udon Thani, Nong Bua Lam Phu, Nakhon Ratchasima and Chaiyaphum.
• East — three provinces: Prachin Buri, Trat and Chanthaburi.
• South — 10 provinces: Chumphon, Ranong, Phang Nga, Krabi, Trang, Surat Thani, Phatthalung, Songkhla, Yala and Narathiwat.

Prachin Buri, Nakhon Nayok, Saraburi and Trang are on DMR’s wider monitoring list but are not included in the specific September 19–21 alert.

The monitored areas extend along mountain ranges in the North and West, as well as foothills in the East and South. The report identifies provinces with accumulated rainfall and active fault lines as areas requiring particular attention.

DMR urges residents to watch streams and unstable slopes

DMR advised people in at-risk areas to monitor rainfall, stream conditions and unusual changes on slopes closely.

Warning signs for residents in landslide- and flash-flood-risk areas include streams changing colour or rising rapidly, unusual noises from mountains, cracks in the ground, and leaning trees or electricity poles. Residents should be ready to evacuate when local authorities issue warnings.