When climatologist Fredrin Tangan looked at a computer weather map and saw three tropical cyclones forming simultaneously across Asia in late November, he first thought of the 2004 disaster movie “The Day After Tomorrow.”
This movie goes beyond the realm of reality as three massive storms plunge the Earth into a new ice age. But there was something about the formation of the weather system swirling on screen that made Tangan stand up.
They weren’t the strongest storms of the year. But they were “not normal,” said Tangan, professor emeritus at the National University of Malaysia.
One of them was swirling near the equator off the coast of Indonesia. Storms are rare in this region because the planet’s rotation is too weak for storms to form. The other was tracking an area of Sri Lanka where tropical storms rarely occur. The third one was scheduled for late in the season, bringing even more rain to the already wet terrain of Vietnam and the Philippines.
“You can see this is a monster,” Tangan said.
The cyclonic storm caused torrential rain and devastating flooding across large swaths of South and Southeast Asia, with some regions recording their second-wettest day on record. More than 1,700 people died, according to CNN tallying statistics from disaster authorities.
Several countries are struggling to recover from the worst flooding in decades. Hundreds of people remain missing, likely washed away in violent floods or buried under thick mud and rubble.
Although the region is accustomed to monsoon rains and frequent flooding, the scale of the human toll and level of destruction has shocked many, with scientists warning that more extreme weather events will become the new normal as the climate crisis intensifies.
“This is a human tragedy. There are multiple situations happening at the same time, which makes it rather unprecedented,” Tangan said.
Scientists have used words to describe the Biblical Flood, which spanned thousands of miles from Sri Lanka to Indonesia, Malaysia, Thailand, Vietnam and the Philippines.
Experts say the disaster was caused by an unusual combination of overlapping and powerful weather systems, amplified by the man-made climate crisis.
Tropical Cyclone Senyar formed just north of the equator in the Strait of Malacca, the waterway between Indonesia’s Sumatra island and the Malay Peninsula. This unusual event may have contributed to the spread of the disaster as the community was not used to experiencing cyclones, Tangan said.
Storms rarely form near the equator because the planet’s rotation is too weak to generate the Coriolis force that rotates cyclones.
In another unusual development, the storm made a U-turn and moved south and east. He added that the Earth’s rotation means storms tend to track west and move north, which is highly unusual in this part of the world.
Meanwhile, Cyclone Ditwa stalked along Sri Lanka’s east and north coasts, dumping heavy rain on the low-lying coastal coastline and central hills. This region also had no experience in dealing with tropical cyclones.
Typhoon Koto’s rains caused flooding and landslides in the Philippines, which has been hit by a series of deadly typhoons and massive flooding, before moving towards already saturated Vietnam.
A cold snap a few weeks ago caused strong winds from the north to blow across the South China Sea, where it collected moisture and released it into Thailand and Malaysia in the form of rain.
In early November, two major typhoons blazed a trail of destruction in the Philippines in less than a week. Phan Wong’s path covered most of the archipelago, and Kalmegi killed at least 200 people before hitting Vietnam as one of the strongest typhoons on record.
Communities in central Vietnam had just barely recovered from widespread flooding and landslides that killed at least 90 people, submerged historic neighborhoods and devastated farmland.
World Meteorological Organization spokeswoman Claire Nuris said one of its weather stations in central Vietnam recorded a nationwide 24-hour rainfall record of 1,739 millimeters.
“This is a really, really huge amount. It’s the second-highest 24-hour rainfall amount known in the world,” she told a news conference in Geneva.
Like a sponge full of water, the land could not accept any more moisture. People had lost their homes and livelihoods and were facing further losses.
The Coto, Senyar and Ditwa rivers followed, “causing continuous rainfall that hit the already saturated river basins,” said Joseph Vasconcillo, a senior meteorological expert at the Philippine Atmospheric, Geophysical and Astronomical Services Administration.
“Once the ground was flooded, more rain quickly turned into severe flooding.”
The surging flash floods and landslides quickly overwhelmed entire communities, catching many people by surprise.
“The combination of the unusual storm track and fragile terrain made the impacts even more extreme,” Vasconcillo said.
Adding to the chaotic cocktail were La Niña and a negative Indian Ocean Dipole, two natural weather phenomena that typically bring above-average rainfall to the region.
La Niña and the Indian Ocean’s negative dipole alone cannot explain the disaster, Vasconcillo said, but they “created a background environment that favors heavy rains.” “The worst effects occurred when this moisture combined with strong storms and fragile terrain.”
In Hat Yai, Thailand’s southern province of Songkhla, floodwaters up to 8 feet high flooded roads, which resident Wassana Sooty described as “like a tsunami.”
On Indonesia’s Sumatra island, the worst hit with at least 883 people killed, rescue teams are still trying to reach villages cut off by washed away roads and collapsed bridges. Abdul Ghani, who lives in the town of Palembbayan in West Sumatra province, spent days searching for his missing wife, showing photos of her to everyone he met. “I hope that the body will be found, even if it’s only part of the hand,” he told Reuters.
A thousand miles away, on the other side of the Indian Ocean, in Sri Lanka, neighborhoods have been washed away and residents continue to search for bodies through thick mud and rubble.
“All I heard was a sound like thunder,” Nawaz Nashra from Kandy’s Arawatgoda village told Reuters. “The house next door collapsed while we were watching. We didn’t have time to warn anyone.”
Southeast Asia and South Asia are among the most vulnerable places on earth to the effects of the human-induced climate crisis, and rich developed countries bear a greater historical responsibility.
Asia is warming almost twice as fast as the global average. Climate change is accelerating rainfall events because warmer ocean temperatures provide more energy for storms to strengthen and warmer air can hold more moisture, squeezing that moisture into towns, cities, and communities.
Researchers say they are now witnessing a pattern of “accumulation of catastrophic events” unfolding.
“What we are witnessing in Southeast Asia is an unrelenting cycle of storms, with extreme monsoon periods that bring heavy rains for weeks on end, and many record-breaking events,” Davide Faranda, research director at France’s National Center for Scientific Research, said in a statement. “We cannot accept this as the norm.”
Urgently phasing out polluting fossil fuels that cause global warming is essential to averting the worst of the climate crisis. But greater investments are also needed to help vulnerable countries adapt to the impacts that are already occurring every year.
“As climate change increases the intensity of heavy rainfall events, stronger warnings, better land-use planning, upgraded infrastructure and investment in nature-based solutions will be essential,” Vasconcillo said.
Other anthropogenic factors may have exacerbated the disaster, such as environmental degradation and widespread deforestation, and it was often exacerbated or abetted by government corruption.
In Indonesia, residents and government officials say decades of deforestation on the island of Sumatra due to illegal logging, mining and palm oil plantations have degraded the landscape, making hilly areas more prone to flooding and landslides. Similarly, in the Philippines, hundreds of thousands of people took to the streets to protest corruption in flood control projects. Meanwhile, Sri Lanka is just beginning to recover from its worst financial crisis in 70 years, with little funding left for infrastructure or public health, according to the World Bank.
At the COP30 summit in Brazil last month, the world struck a new agreement calling for a tripling of funding to help countries adapt to the increasingly severe impacts of the climate. But countries could not agree on a roadmap to transition away from fossil fuels, and there were no clear commitments on deforestation or funding.
“The science is really clear: Things are getting worse,” said climate scientist Tangan. “It’s time for the world and governments to not only get serious about remediating climate change, but also to ensure that their own backyards can cope with the impacts of climate change,” he added.
“We don’t want our country to become poorer, our people to become poorer, and more families to die because of it.”
More rain is expected in Sumatra and Sri Lanka this week. A new storm is forming in the east of the Philippines.
