'No warning' - residents reel from deadly flood after typhoon bursts Taiwan lake

When the floodwater came rushing down from the mountain, Awa and her husband tried to get to their car – but it was already too late.

"It was like a river outside and cars were floating. Everything started drifting," said the 42-year-old bookstore owner. The couple sought refuge on the second floor of their shop in Guangfu township, trying to save as many books as possible.

"I'm still in shock. I just can't imagine how this could have happened," she said.

Like many Taiwanese, Awa is reeling from the unexpected deadly destruction caused by Super Typhoon Ragasa, even though the island was not in the direct path of the strongest storm the world has seen this year.

The breaching of a barrier lake – formed after landslides triggered by another typhoon blocked rivers in a remote mountain valley in July – is the main cause of extensive damage in the eastern county of Hualien, said Huang Chao Chin, the deputy commander of Taiwan's Central Emergency Operation Centre.

People who were in the path of the deadly wall of water that swept down the mountainside stood little chance as it washed away a bridge, uprooted trees and submerged vehicles.

Many of those who died were elderly, trapped by water surging into their homes.

An aerial view showing the mud left in the streets as floodwaters recede

The Matai'an Creek barrier lake is about 11km (7 miles) away from downstream communities.

It held some 91 million tonnes of water, enough to fill 36,000 Olympic-sized swimming pools. About three-quarters of that water was suddenly released after the lake burst its banks on Tuesday, killing at least 14 people and injuring 32 others. Forty-six people are still unaccounted for.

Emergency services said the water was metres deep in Guangfu, the town worst hit. It rose as high as the second floor of a house in some places and was about one-floor deep in the town centre.

The force of the water unleashed by the lake burst could be compared to a tsunami, said Chen Wen Shan, emeritus professor of geology at National Taiwan University.

"The kinetic energy could even be greater than that of a tsunami. The flow speed can exceed 100km/h [62mph] per hour," he told the BBC. "Although the energy decreases once it reaches the plains, it still remains powerful and fast - far beyond what a typical river embankment can handle."

Survivors in Guangfu said they received no warning from the authorities immediately before disaster struck.

But Prof Chen said the academic community had sounded the alarm bell before, as universities were closely monitoring the water level of the barrier lake and worked with authorities on the emergency plans.

"With the typhoon approaching, we could estimate the rainfall. We knew the water could overflow the lake this time. Part of the dam also collapsed, which caused a large volume of water. But even this volume was within our estimates," he said.

"Failing to evacuate residents properly is one of the factors why the disaster became so severe."

A school administrator said he was shocked by the damage in Guangfu

On Monday 22 September, a day before Ragasa neared the island, Hualien authorities issued warnings, evacuated about 7,000 people and set up three evacuation centres. Meanwhile, the central government repeatedly urged the county administration to accelerate the evacuations.

But the evacuation was "not mandatory" and local officials only called on the public to go to higher ground, Hualien county councillor Yang Hua-mei told the BBC.

It was shortly before 15:00 local time (07:00 GMT) on Tuesday when the barrier lake overflowed. Officials had expected it would take the floodwater two hours to reach inhabited areas downstream and only people living near the river would be affected.

But within an hour, vast quantities of water were pouring into Guangfu Township, where 12,000 people live.

"There were no special flooding warnings and no broadcast," an administrator of a high school in Guangfu told the BBC on condition of anonymity. The school was designated an evacuation centre, so he'd originally been tasked with helping evacuees.

He said he'd just finished lunch at around 15:00 when he heard the lake had burst its banks.

"Within 10 minutes, water spread to the campus from the street. The 400-sq-mile sports ground was submerged," he said. Chairs, tables, refrigerators and even cars were soon floating.

"If I'd still been on the street, I wouldn't have been able to reach higher ground. There were lots of objects floating in the water. I could have been hit or even electrocuted."

The administrator said officials might have underestimated Ragasa's impact - the lake had not breached its banks when a weaker typhoon hit last month.

Since last week, County Mayor Hsu Chen-wei had been on a trip to South Korea to promote tourism. She returned to Hualien on Monday evening – reportedly after a call from the interior minister.

Residents are using spades to clear up mud inside properties in Hualien

Those like Awa and her husband at the bookshop, and the school administrator, were able to get to safety in time.

But many of the victims of the flood were elderly. Most bodies were found on the ground floor of houses, according to local media.

"Rural elderly residents usually receive information through door-to-door communication. It's unclear how the local authorities had informed them and managed the situation," said Awa. Hualien's population is ageing, and many of its older residents don't use smartphones.

"Many elderly residents are also bedridden because of chronic illness, and no one could help them," Ms Yang said.

But Prof Chen pointed out there were no quick solutions. For barrier lakes made up of harder bedrock, small blasting operations can be carried out to divert the water, he said. But in this case, the lake is formed of looser earth and rocks.

"Also, there are no roads leading to the mountains, so heavy machinery cannot be deployed."

Taiwan has plenty of experience of barrier lakes - 88 have been formed on the island since the 1970s, according to Taiwan's Public Television Service. Of those 57% were formed after typhoons; 23% from earthquakes. Most disappear within a year, although four have been there for decades.

But Taiwan's public have little understanding of barrier lakes, former interior minister Lee Hong-yuan, a trained civil engineer, told local media. He said many researchers were witnessing the bursting of a barrier lake for the first time.

Awa and her husband's bookshop moved to its current location a few months ago

Hualien, which is nearly 90% mountainous, is no stranger to natural disasters, either. The county is often the first location on Taiwan to face typhoons, and its location on the Pacific Ring of Fire means it's prone to earthquakes.

The calamities in the past two years, including a fatal magnitude 7.1 earthquake in 2024, have devastated the county's tourism industry, Ms Yang said. Many scenic spots and routes in the world-famous Taroko Gorge National Park are still shut after the quake.

The county also has the largest Indigenous population in Taiwan, with Awa's husband being one of them. The couple started the bookshop four years ago with the mission of preserving the history of Indigenous people - and it moved to its current location just a few months ago.

Now, the bookshop is drenched in mud and they are taking stock of the damage.

"I am really sad because some of the books have already run out of print," she said.

But at least she and her husband are safe.

Others in the town are having to cope with losing loved ones, or worrying about relatives and friends who are hurt or those who are still missing.

A tearful Ms Shih, whose 87-year-old mother was killed, told local media that her body was covered in debris inside their home.

"We hope the government and police can contact us soon and help recover my mother's body so she can be laid to rest."

Additional reporting by Lok Lee of BBC News Chinese in Taipei