Hong Kong Paralyzed by Historic Rainfall, Second-longest Black Rainstorm Signal Issued

Hong kong ground to a halt Tuesday as record-breaking torrential rainfall overwhelmed teh city, prompting its second-longest black rainstorm warning in history. The signal, indicating the highest level of threat, remained in effect for over 11 hours, causing widespread flooding, business closures, and school suspensions. The Hong Kong Observatory reported 358.8mm (14.1 inches) of rainfall at its Tsim Sha Tsui headquarters by 5pm, marking the highest daily rainfall for the month of August since record-keeping began in 1884.

Unprecedented Rainfall and Prolonged Warning

This latest deluge is the fourth time a black rainstorm signal has been issued in Hong Kong within the past eight days, highlighting an unusually wet period for the region. The warning was initially raised at 5:50 am and downgraded to amber at 5:05 pm, lasting a total of 11 hours and 15 minutes. While all rainstorm signals were briefly cancelled at 6:15 pm, an amber warning was re-issued at 10:55 pm and lifted at 12:30 am Wednesday.

The extended duration of the black rainstorm signal – 11 hours and 15 minutes – is second only to the signal issued between September 7-8, 2023, which lasted 16 hours and 35 minutes. Hong KongS rainstorm warning system was first implemented in 1992.

Impact and Response

Authorities suspended all school classes as a precautionary measure,but stopped short of declaring “extreme conditions,” which would trigger a more complete shutdown. The MTR (mass Transit Railway) experienced meaningful disruptions,with several lines experiencing delays and temporary closures due to flooding. Landslides were reported in several areas, including on Hong Kong Island and in the New Territories, prompting evacuations of residents in vulnerable locations. The Hong Kong government opened temporary shelters for those displaced by the flooding, particularly in low-lying areas like Sham Shui Po and north Point.

Businesses across the city,particularly in areas prone to flooding like Causeway Bay and Mong Kok,were forced to close for the day. The Hong Kong Stock Exchange operated normally, but many employees were unable to commute to work.The hong kong International Airport experienced flight delays and cancellations, impacting thousands of travelers.

Context and Future Outlook

Hong Kong’s vulnerability to extreme rainfall events is increasing due to climate change. The city’s dense urban development and limited drainage capacity exacerbate the impact of heavy downpours. The Hong Kong government has invested in infrastructure projects aimed at improving drainage and flood control, including the construction of underground stormwater storage tanks and the widening of rivers. However, experts warn that more needs to be done to adapt to the changing climate and mitigate the risks of future flooding events. The current rainfall event underscores the urgent need for continued investment in climate resilience and disaster preparedness.