Taiwan's weather authorities advised six counties and cities in the centre and south to guard against heavy rain. Strong overnight rainfall raised flooding concerns in low-lying areas of the south.

Downpour after drought

The rainfall added more than 10 million tonnes to Zengwen Reservoir in a day, the largest daily inflow since Typhoon Bavi passed. Managing storage levels is a recurring annual problem in southern Taiwan, so reservoir inflow is in itself a positive signal.

But rainfall concentrated into a short window creates hazard before it creates storage. Water carrying sediment from hillsides increases the treatment burden, and once it exceeds urban drainage capacity it becomes flooding.

Ferry routes affected

Sea conditions also deteriorated. The Xiaoliuqiu ferry route will operate morning sailings only on Saturday and suspend service entirely on Sunday. Because the route concentrates its sailings on weekends when tourist demand peaks, cancellations hit local tourism immediately.

Authorities urged residents in low-lying areas to stay away from rivers and to check drainage channels. Falling rocks and landslides were flagged as risks on mountain roads.

With observations pointing to wider swings in rainfall patterns this year under El Niño conditions, the possibility of similar episodes recurring into autumn is being raised.