Hualien — A wall of water roared off a mountain above a quiet township in eastern Taiwan on Tuesday afternoon, a sudden surge that ripped away a bridge, churned streets into rapids and left families searching for each other in the mud. By Thursday, September 25, authorities had revised the death toll to 14 and continued to account for the missing as Super Typhoon Ragasa’s long arc through Taiwan, Hong Kong and southern China shifted from survival to an exacting cleanup and a review of what went wrong Taiwan lowers the toll.
The disaster in Hualien County did not come from a broken concrete dam or a failed reservoir. It was a barrier lake, a natural dam formed when earlier landslides clogged a high valley above Guangfu Township, quietly piling up millions of tonnes of water through summer and early autumn. When Ragasa’s outer bands unloaded sheets of rain this week, the makeshift dam overtopped and collapsed, releasing a brown surge that bulldozed through orchards and neighborhoods before the water level fell back, leaving sludge, scarred homes and a vanished road link where the span once stood (CNA reports).
Officials said the lake had been mapped in July, after satellite monitoring spotted the formation and engineers confirmed that a landslide had dammed a tributary of the Matai’an Creek. The natural dam was estimated at roughly 120 meters in height. Before the breach, the impounded water stretched roughly half a kilometer long and more than a kilometer wide. When it let go, about 60 million tonnes rushed downstream, an estimate that roughly equates to 36,000 Olympic pools, according to Reuters. The scale explains the violence witnesses describe, the speed with which first floors filled and cars were lifted and carried like toys.
Numbers stabilized slowly. On Wednesday, the island’s emergency services reported 17 dead and more than 30 missing. By Thursday, September 25, a reconciliation of registries lowered the confirmed toll to 14, with the missing pared down as authorities traced people who had been out of contact, CNA confirms 14 dead. The count could still shift as relatives file reports and responders reach isolated hamlets along the valley. What is not in dispute is the concentration of loss among older residents who were at home when the torrent punched through ground floors.
Taiwan’s premier framed the task ahead as both urgent and corrective. “Beyond mourning the victims, we must investigate the causes of death, which predominantly occurred on the first floors,” he told a Cabinet meeting on Thursday. “Clarifying these factors is essential for refining future evacuation protocols.” In a separate message to rescuers and local officials he urged teams to “seize the golden rescue window,” a phrase that has guided flood response doctrine across Asia.
The debate over evacuation advice has already begun in villages up and down the valley. In some communities, residents were told to move to second floors rather than leave, a vertical evacuation tactic that can work when flood depths are shallow but fails when a true surge arrives. Village heads on the valley floor say the people who did make it out early were those covered by clear mandatory orders, with pickup points predesignated and buses standing by. Others waited, assuming the water would stop at ankle or knee height, assumptions swept away when the influx topped furniture and window sills (renewed evacuation orders).
High in the mountains behind Guangfu, the barrier dam remains a hazard, though much reduced. Engineers must assess slopes that are still unstable after a major earthquake last year and determine whether any further impounded water could pose risks if new rain bands pass over the ridge. The government has ruled out blasting the natural dam to accelerate drainage, warning that explosives could trigger fresh slides that funnel more debris into the valley. As the agriculture minister put it, the red warning stays in place and people should stay clear of the river (minister’s caution).
Downstream, the physical geography has already changed. A key bridge on the main highway was snapped at both ends, the deck gone and the piers marooned, cutting the most direct road link to the township. Rail service to Guangfu’s small station has been restored, but travel in and out still relies on detours and convoy controls while excavators carve through deep mud and crews clear houses where the entrances were sealed by silt local transport closures. In farm rows, fruit trees stand in slurry up to their grafts. The cleanup will take weeks, and planting cycles may be lost for a season.
Ragasa’s footprint extends well beyond Taiwan’s east coast. The storm put Hong Kong on pause midweek as the city hoisted its highest typhoon signal, lashed by gale-force winds that sent surf over sea walls and seawater into building lobbies. A luxury hotel at the island’s south saw its glass doors shattered and a tide pouring across the marble, a scene captured on phones as staff herded guests away from the entrance. More than a hundred people were treated for injuries as trees fell, roads flooded and transit halted. The airport canceled flights for roughly a day and a half before reopening with a staggered schedule on Thursday morning, Hong Kong reopens, T10 aftermath. For broader context on the city’s storm playbook, see our earlier coverage that Typhoon Ragasa shuts Hong Kong.
On Thursday afternoon, the cleanout in Hong Kong felt almost routine, a testament to muscle memory after severe seasons. Crews mapped downed trees, pumped out underpasses and shored up broken fences. Small shopkeepers and stall owners pulled soaked packaging into piles, tallied losses and stood in doorways weighing how much stock to replace. One proprietor who sells premium tea and cigarettes said the water rose higher than anyone in the building expected, ruining boxes stacked for the Mid-Autumn trade and wiping out inventory that was already squeezed by thin margins.
Across the border in mainland China, Ragasa made landfall near Yangjiang in Guangdong province late Wednesday, clipping some of the world’s densest belts of manufacturing and logistics. Authorities ordered closures in at least ten cities ahead of the storm, relocating more than two million people as a precaution, and then tracked a second landfall at Beihai in Guangxi as the system weakened to a tropical storm. Southern coastal districts that rely on tourism, from island beaches to boardwalks, spent Thursday clearing blown sand and tree limbs from roads. In Zhuhai, local reports described widespread inundation in low-lying neighborhoods. In Shenzhen, the tech hub’s broad boulevards were carpeted with leaves and branches until teams had them cleared by nightfall.
By Thursday morning, regional media said Ragasa had eased again as it tracked west, its winds diminished but its rains still heavy enough to push up flood risk across southern China and onward toward Vietnam (regional wrap). China’s marine forecasters had flagged the threat ahead of time with a red storm surge warning, including wave heights that could topple waterfront barriers in exposed coves and capes along the Guangdong coast. The signal let port managers and shipping agents pull vessels into safer anchorage and stage tugboats for quick assists when berths reopened.
Ragasa tested infrastructure and preparedness but also showed where investments have paid off since the punishing seasons of the 2010s. In Hong Kong, the stock exchange stayed open throughout, and the resumption of airport operations within hours of the wind signal being lowered kept cargo moving. In Shenzhen and neighboring cities, waterlogging was real but drains cleared faster than in past gales, evidence of trenching and retention projects that often go unnoticed until a storm arrives. For historical comparison on top-tier alerts, our earlier report on Signal No. 10 during Wipha remains instructive.
None of that lessens the shock for families along the Hualien valley, where the topography traps water and sediment. Here, preparedness means mapping invisible threats and communicating risk to older residents who may not use smartphones. Community leaders have pointed to a digital gap that complicated outreach in the days before the breach. Briefings were held, some in the Amis indigenous language, but not everyone absorbed the change from a standard flood warning to a once-in-decades torrent. In some villages, those who gathered at schools and town halls escaped the worst. Elsewhere, households that opted to stay indoors on higher floors were hit when the surge rose higher than anyone predicted.
Inside homes, mud sits like concrete around table legs and along staircase risers. Family photos are muddy at the edges. Owners shovel sludge toward the curb one scoop at a time while neighbors rig hoses to flush entryways and windowsills. Tractors pull stalled sedans out of alleys. A church team lays out bottled water, gloves and bleach on folding tables. Road crews mark sinkholes with striped boards and string. Rescue dogs move from house to house, pausing at piles of driftwood where a door might be buried beneath.
The physics of the barrier lake made this disaster unusual, but not unimaginable. Landslide-dammed lakes form regularly in Taiwan’s steep terrain, especially after typhoons and strong earthquakes loosen rock columns and saplings along gullies. Most of the time they drain gradually. The risk spikes when a follow-on storm arrives with enough rainfall to top the temporary dam and chew a channel across it. Once it overtops, the breach can widen in minutes, and a slow river becomes a flood pulse with little warning for those living below. That is why authorities keep helicopter patrols and satellite feeds trained on headwaters after major storms, even when the lights are back on in the cities. When earlier cyclones forced evacuations on the island, the experience under Typhoon Kong-Rey offered a foretaste of hard choices now facing the east coast.
Experts who study cyclones in the Western Pacific point to a clear signal in recent years. Warmer seas and moister air have loaded the dice for storms that intensify quickly and carry more rain. That does not mean every season will be worse than the last, but when a system like Ragasa spins up over very warm water and then parks its rain bands along the windward flank of a mountain range, the hydrology gets dangerous, first in the hills, and then wherever those hills drain. Cities can harden harbors, elevate subways and seal tunnel entrances. Valleys need new kinds of risk maps and drills that acknowledge how fast a barrier lake can flip from a line on a satellite image to a lethal surge. In the wider region, the calculus around early moves is familiar from mass evacuations in the Philippines.
For Taiwan, the checklist after the rescue phase will be extensive. Investigators will reconstruct timelines for alerts and advisories. Hydrologists will calculate the friction and slope of the gullies that fed the wave through Guangfu, and estimate peak flows from high-water marks and debris lines. Social workers will review calls to older residents who live alone or with limited mobility, and local governments will consider whether sirens, door-to-door calls and neighborhood captains should be added to push alerts that many seniors may never see. Civil engineers will examine alternatives to blasting, including controlled drilling and siphoning where access is safe, so similar lakes can be lowered ahead of the next storm.
On the mainland, the focus is already shifting to economic normalization. Southern China’s airports and ports are clearing backlogs. Energy traders are watching any impact on pipeline and refining operations along the Guangdong coast, though early signs suggest limited disruption beyond storm surges and wind damage at waterfront facilities. Tourism bureaus are pushing beach reopenings where it is safe. In Hong Kong, municipal crews are methodically cataloging damaged street trees and replanting, a small act of renewal that nevertheless changes how a city looks and breathes after a storm tears at its canopy.
There is no single storm story this week, only a chain of them, each shaped by geography and demographics. In urban Hong Kong, where glass towers meet defended shorelines, Ragasa was a storm to endure and then sweep away. In Guangdong’s cities, it was a test of closures, relocations and a rapid reset for factories and schools. In Hualien’s hills, it was a fluke of geology made lethal by timing, topography and the vulnerability of older residents whose first instinct is to shelter at home. As the Western Pacific enters the tail of its typhoon season, the lesson is not only to prepare for wind and surge. It is to watch the mountains, meter by meter, because the danger now often starts where the roads end. For readers tracking cross-region impact snapshots as the storm weakens toward Vietnam.
By Thursday night, trains were running again to Guangfu’s station and supply trucks threaded detours to bring in food, clean water and fuel. The highway bridge will take months to replace. Families will sift what can be saved and throw the rest away. In Hong Kong and across southern China, the storm’s signature will linger in warped floors and salt-white streaks along seaside walls. The memory will linger longer in the valley. Ragasa has moved on, downgraded and already less organized on weather maps, but the people in its wake are not finished with it yet.
