FLASH UPDATE #2 – Tropical Cyclone YAGI & Southwest Monsoon
Countries under monitoring: Cambodia, Lao PDR, Myanmar, Philippines, Thailand, and Viet Nam
OVERVIEW: According to PAGASA, on 2 September at about 1300H UTC+7, TC YAGI made landfall in Casiguran, Aurora in the Philippines. TC YAGI continued to traverse mainland Luzon then slightly weakened as it interacted with the mountains of Northern Luzon. TC YAGI accelerated over northern Luzon and has intensified into a typhoon. The tropical cyclone is expected to intensify and may reach its peak intensity by late Friday or early Saturday (PAGASA). Based on forecasts, YAGI may pass by Hainan, China before moving towards Northern Viet Nam. Meanwhile, the enhanced Southwest Monsoon is now prevailing over the western section of Luzon and is expected to bring moderate to intense rainfall from today until the next 2-3 days.
PHILIPPINES
IMPACTS: Based on NDRRMC Situation Report issued on 4 September 2024 at 0700H UTC+7, the effects of TC YAGI and the Southwest Monsoon had caused the following impacts:
- 12 deaths, 11 injuries, 7 missing persons, 64K displacements, and a total of 547K affected population (150K families) in 8 regions, 27 provinces, 142 cities/municipalities
- 323 evacuation centres activated
- 589 damaged houses (of which 51 are totally damaged)
- 79 road sections and 19 bridge sections were affected (36% are still unpassable)
- 17 seaports had interrupted operations, and 24 domestic flight were cancelled
- 456 cities/municipalities had work suspension while 659 have cancelled classes
- 228 reported flooding incident
HAZARDS:
TROPICAL CYCLONE YAGI
- Heavy Rainfall – According to PAGASA,TC YAGI shall continue to bring moderate to heavy rainfall (50-100 mm) is possible in Ilocos Region.
ENHANCED SOUTHWEST MONSOON
- Heavy Rainfall – According to PAGASA, moderate to intense rainfall are expected in the following areas over the next 2 days:
- 4 Sept: 100-200 mm in Pangasinan, Zambales, Bataan, and Occidental Mindoro; 50-100 mm in northern Palawan including Calamian, Cuyo, and Cagayancillo Islands, Metro Manila, Cavite, Batangas, Rizal, Laguna, Bulacan, Pampanga, Tarlac, Nueva Ecija, La Union, and Benguet
- 5 Sept: 100-200 mm: Zambales, Bataan, and Occidental Mindoro; 50-100 mm in northern Palawan including Calamian, Cuyo, and Cagayancillo Islands, Cavite, Batangas, Bulacan, Pampanga, and Pangasinan
ANTICIPATED RISKS:
- Under these conditions, flooding and rain-induced landslides are likely, especially in areas that are highly or very highly susceptible to these hazards as identified in hazard maps and in areas with significant antecedent rainfall. (PAGASA)
- As of 4 September at 0400H UTC +7, major riverbasins Pampanga, Agno, NCR/Marikina Laguna de Bay, Cagayan, and Angat Sub-basin, have been placed under flood watch.
- As of 0020H UTC+7, water level at the La Mesa Dam which affects cities in the northern National Capital Region (NCR) has reached overflow level. Water level dams and waterways in the vicinity of the NCR and CALABARZON are being closely monitored; several of these are nearing alarm and critical levels as moderate to heavy rainfall persist.
- Flood advisories and bulletins that warn the public of widespread and severe flooding have been issued in areas within the vicinity/floodplains of these riverbasins and waterways.
PREPAREDNESS AND RESPONSE:
- The NDRRMCOC maintains RED Alert Status ICOW with TC YAGI and the Southwest Monsoon.
- NDRRMC issued memoranda for 1) EPR Protocols, and 2) activation and standby status of National Response Clusters ICOW TC YAGI and Southwest Monsoon.
- Emergency alert and warning messages were disseminated to affected provinces.
- Regular coordination meetings are conducted by NDRRMC, regional and local authorities, PAGASA and related agencies
- Continuous monitoring and dissemination of warnings and advisories are being conducted.
- Pre-Disaster Risk Assessment were conducted on 31 August and 1 September by the NDRRMC in preparation for the impacts of TC YAGI and the Southwest Monsoon.
- Local authorities have issued class and work suspension following early warning advisories on heavy to intense rainfall and flooding.
- Communities in areas highly susceptible to flood and landslides were evacuated; evacuation centres have been activated to serve displaced population.
- PAGASA closely monitors and regularly issues advisories on the developing weather conditions and disturbances. PAGASA also continues to conduct press briefings to provide detailed updates on the weather and hydrometeorological situation.
- NDRRMC, regional and local authorities are closely monitoring PAGASA advisories and closely coordinates with related agencies to ensure the safety of the affected and at risk communities.
- PAGASA advises the public and disaster risk reduction and management offices concerned to take all necessary measures to protect life and property. Persons living in areas identified to be highly or very highly susceptible to these hazards are advised to follow evacuation and other instructions from local officials
FORECAST AND ESTIMATED IMPACTS IN MAINLAND SOUTHEAST ASIA
FORECAST: As of 0400H UTC+7 today, TC YAGI has left the Philippine Area of Responsibility and is now located in the eastern sea area of the North East Sea. TC YAGI is expected to move generally westward until tomorrow (5 September). Further intensification is likely as TC YAGI continues tracking west northwest towards the Viet Nam North East Sea, passing by Hainan, China before moving towards Northern Viet Nam. According to the Mekong River Commission (MRC), heavy rainfall is forecast for several provinces in Mainland Southeast Asia and TC YAGI is expected to affect the Lower Mekong River Basin from 8 September.
INTENSITY & STRENGTH: Maximum sustained winds of 130 km/h, and wind gusts up to 157 km/h
MOVEMENT: Moving west northwest at about 15 km/h
HAZARDS & ANTICIPATED RISKS:
CAMBODIA
- Heavy Rain in the next 24 hours in Battambang, Koh Kong Pailin, Mondul Kiri, Preah Vihear, Stung Treng, and Ratana Kiri. Heavy rain can cause flash floods in Stung Treng and Ratana Kiri. (MRC)
- Moderate to heavy rainfall is expected from 5-9 September (MRC)
LAO PDR
- Heavy Rain in the next 24 hours in Vientianne, Khammuane, Attapeu, and Champasak (MRC)
- The northern part of Lao PDR is anticipated to experience heavy rain from 8-9 September due to the impact of TC YAGI. (MRC)
- According to the ASEAN DMRS, at most 7.6-15.2 cm of Tropical Cyclone-associated rainfall is possible over Northern Lao PDR.
MYANMAR
- Estimated rainfall impacts of TC YAGI may extend to the regions bordering Lao PDR and Thailand (ASEAN DMRS)
THAILAND
- Heavy Rain in the next 24 hours in Nakhon Ratchasima, Buriram, Sisaket, Surin, and Ubon Ratchathani (MRC)
- From 7-8 September, some areas in the North, the upper Northeast and the East are forecast to have very heavy rain due to the effects of TC YAGI. (TMD)
- In Northeast, Central regions including Bangkok and its vicinity, the East and the South, heavy to very heavy rain and accumulated rain may cause flash floods and forest runoff, especially on hillsides near waterways and lowlands throughout the period. (TMD)
VIET NAM
- According to the NCHMF update as of 1000H UTC+7, the North East Sea is expected to have strong winds of level 9-11, near the eye of TC YAGI, level 12-14, gusting to level 17; rough seas.
- For 4 September, storms are likely in the eastern sea of ??the North East Sea; the central and southern East Sea (including the waters of the Truong Sa archipelago), the waters from Binh Thuan to Ca Mau, Ca Mau to Kien Giang and the Gulf of Thailand will have showers and thunderstorms. In the afternoon and evening of 4 September, the Central Highlands and the South will have rain, moderate rain and scattered thunderstorms, with rainfall ranging from 20-40mm, locally over 70mm. The Central and South Central regions will have scattered showers and thunderstorms, with rainfall ranging from 10-30mm, locally over 60mm. (NCHMF, VDDMA)
- From 5-7 September, as TC YAGI continues to intensify, strong winds can reach level 15, and gusting above level 17 near the eye of the TC. (NCHMF)
- Thunderstorms may cause tornadoes, lightning, hail and strong gusts of wind. (NCHMF, VDDMA)Heavy rain and localized heavy rain can cause flooding in low-lying areas; flash floods in small rivers and streams, and landslides on steep slopes. (NCHMF, VDDMA)
- Heavy rain in the next 24 hours in Dak Lak, Kon Tum, and Gia Lai. Heavy rain can cause flash floods in Gia Lai and Kon Tum (MRC)
- According to the ASEAN DMRS, at most widespread to severe damage (TAOS) over Northern Region of Viet Nam; and at most 30.5-61 cm of Tropical Cyclone-associated rainfall is possible over Northern Viet Nam.
PREPAREDNESS & RESPONSE:
- The National Hydrometeorological Services of Cambodia, Lao PDR, Myanmar, Thailand, and Viet Nam are closely monitoring the development of weather and issue regular weather updates.
- Early warning information and advisories are proactively provided to the public and communities as risk of the potential effects of the monsoon rains and TC YAGI.
- Authorities closely monitors these situations and proactively coordinates with relevant agencies to prepare for potential effects of the weather disturbances in their respective areas of responsibilities.
- In Viet Nam, coastal provinces and cities from Quang Ninh to Phu Yen proactively respond to TC YAGI near the East Sea according to Official Dispatch No. 6475/CD-BNN-DD dated 2 September 2024 of the Ministry of Agriculture and Rural Development. In addition, the Prime Minister issued Official Dispatch No. 86/CD-TTg dated 3 September, 2024 directing urgent response TC YAGI and floods. (VDDMA)
The AHA Centre will continue to monitor for further developments and issue necessary updates.
DATA SOURCES
ASEAN Disaster Monitoring & Response System (DMRS), ASEAN Disaster Information Network (ADINet); Pacific Disaster Center (PDC Global); ASEAN Specialised Meteorological Centre (ASMC);
Cambodia: NCDM;
Lao PDR: NDMO Lao PDR;
Myanmar: DDM;
Philippines: NDRRMC-OCD, PAGASA;
Thailand: DDPM, TMD;
Viet Nam: VDDMA, NCHMF;
Verified news media agencies;
