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.

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.

Emergency services reported that the water rose as high as the second floor of a house in some places and was about one-floor deep in the town center. Survivors in Guangfu said they received no warning from the authorities immediately before disaster struck. Authorities had predicted the floodwaters would take two hours to reach inhabited areas downstream, but the heavy deluge poured into Guangfu Township within an hour, where 12,000 residents live.

On Monday, a day before Ragasa hit, Hualien authorities issued evacuation warnings and set up evacuation centers, but attendance was not mandatory. Local officials had only advised the public to go to higher ground. With the disaster unfolding, many rural elderly residents depended on door-to-door communication for information, raising concerns about the adequacy of the advanced warning.

Taiwan has experience with barrier lakes, having managed many created by landslides over decades, but the rush of water from this latest incident is noted as unprecedented.

As the community comes together to recover, stories of loss and despair surface, with many residents mourning lost loved ones and ruminating on the inadequate response that added to the tragedy.