Deadly Floods Sweep South and Southeast Asia as WMO Boosts Early Warning Efforts

The WCM consolidates authoritative weather, water and climate information from WMO Members, ensuring humanitarian agencies receive fast, accurate guidance.

Weeks of intense monsoon rains and repeated tropical cyclones have unleashed catastrophic flooding across South and Southeast Asia, killing hundreds, displacing millions, and causing widespread economic devastation. National Meteorological and Hydrological Services are working around the clock to issue forecasts and coordinate emergency responses, while the WMO Coordination Mechanism (WCM) provides critical expert guidance to humanitarian agencies.

Countries worst affected include Indonesia, the Philippines, Sri Lanka, Thailand and Viet Nam, where simultaneous climate-driven hazards—heavy rainfall, storm surge, landslides and overflowing rivers—have stretched emergency systems to their limits.

The crisis highlights what the WMO State of the Climate in Asia reports have long warned: rising temperatures are amplifying rainfall extremes, making the region one of the world’s most vulnerable hotspots for flood disasters.

“Asia-Pacific Faces the World’s Most Intense Tropical Cyclones”

WMO Secretary-General Celeste Saulo addressed the Typhoon Committee’s meeting in Macau, China, underscoring the urgent need for coordinated regional action:

“Record-breaking rainfall, storm surges and floods displace millions and cause billions in economic losses. No single institution or country can tackle these challenges alone.”

She praised regional cooperation bodies, such as the Typhoon Committee and the WMO/UNESCAP mechanisms, as essential platforms for joint forecasting, response planning and climate resilience.

WMO Coordination Mechanism Provides Life-Saving Early Warnings

The WCM consolidates authoritative weather, water and climate information from WMO Members, ensuring humanitarian agencies receive fast, accurate guidance.

Recent WCM updates included:

• Seasonal Climate Outlooks predicting above-normal rainfall across Southeast Asia and the Maritime Continent

• Global HydroMet Weekly Scans warning of heavy rain, thunderstorms, storm surge and landslides across Sri Lanka, southern India, Thailand, Viet Nam, Indonesia, Malaysia and the Philippines

• Alerts on potential tropical cyclone formation and movement

These early warnings helped governments prepare—though the scale of rainfall overwhelmed flood defences in several countries.

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Country Impacts

Indonesia: Tropical Cyclone Senyar Causes Major Loss of Life

Northern Sumatra experienced extraordinary rainfall from Tropical Cyclone Senyar—a rare cyclone so close to the equator. According to BNPB (2 December 2025):

• 604 dead

• 464 missing

• 2,600 injured

• 1.5 million affected

• 570,000 displaced

• 50 districts impacted

Landslides and river overflows destroyed homes, bridges and farmland, making this one of Sumatra’s worst disasters in recent decades.

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Viet Nam: Historic Rainfall and Widespread Flooding

Viet Nam’s south-central provinces faced relentless rainfall from November storms and the impacts of Storm Koto:

• Nearly 100 deaths reported

• Rainfall totals surpassed 1,000 mm, with Dak Lak receiving up to 1,200 mm

• A station in Hue City recorded 1,739.6 mm in 24 hours, potentially setting a new Asian and Northern Hemisphere record, pending WMO verification

• Rivers including Ky Lo, Ba and Dinh Ninh Hoa exceeded historic flood levels

Agriculture suffered millions of dollars in losses, while tourism and cultural heritage sites were severely affected.

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Philippines: Recovering from Back-to-Back Typhoons

In early November, the Philippines was battered by:

• Typhoon Kalmaegi (Tino) – over 220 deaths, 2.4 million affected

• Typhoon Fung-Wong (Uwan) shortly after

These storms add to an unprecedented number of cyclones that struck the country since 2024.

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Sri Lanka: Worst Flooding in Decades

Cyclonic Storm Ditwah devastated Sri Lanka with record rainfall:

• Nearly 1 million affected

• 212 deaths, 218 missing

• Widespread landslides and river overflows

• All 25 districts impacted

The storm moved from the east coast back into the Bay of Bengal, intensifying flooding. Without WMO guidance, authorities say casualties would have been far higher.

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Thailand: Deadly Floods Hit Southern Provinces

Southern Thailand experienced exceptional rainfall—up to 370 mm, equivalent to a 300-year return period:

• 178 deaths

• 2.3 million affected

• 9 provinces and 74 districts flooded

• Hat Yai, the region’s largest city, was heavily impacted

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WMO Action: Strengthening Early Warning Systems

WMO continues to play a leading role in improving flood forecasting and early warning systems globally through:

1. Flood Forecasting Framework & Initiative (FFI)

Used in over 70 countries, integrating:

• Satellite precipitation

• Radar data

• High-resolution numerical models

These help anticipate flash floods hours before they occur.

2. Severe Weather Forecasting Programmes (SWFP)

Supporting national forecasters in South and Southeast Asia with training, tools and operational products.

3. South Asia HydroMet Forum (SAHF)

Improving hydro-meteorological services under the WMO-implemented CREWS South Asia Project.

4. Early Warnings for All Initiative

A global campaign to ensure every person on Earth is protected by early warning systems by 2027.

5. New Community of Practice on Flood Forecasting (2025)

A collaborative hub for experts worldwide to exchange innovations, strengthen capacity and advance early action.

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A Call for Enhanced Global Cooperation

As flood disasters intensify under a changing climate, WMO stresses that international cooperation, science-based early warnings and sustained investment in resilience are essential to prevent further tragedies.