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 thestrongest 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 lakeis 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.
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“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, asuniversities were closely monitoring the water level of the barrier lakeand 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.” Additional reporting by Lok Lee of BBC News Chinese in Taipei
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