Hong Kong sets rainfall record as deluge disrupts flights

HONG KONG – Hong Kong set a rainfall record for August after violent storms lashed the city on Aug 5, leading to flight delays and commuter chaos.

About 356mm of precipitation was recorded at the Hong Kong Observatory’s headquarters until 2pm, a daily high for the month, according to the weather agency.

The bureau cancelled rain warnings on the evening of Aug 5 after downgrading from its highest alert, but said dangerous showers and flooding were still possible.

The heavy rain and gusty winds have led to growing disruptions at the Hong Kong International Airport.

At least 431 passenger and cargo flights were delayed, with 12 services cancelled as at 4pm, according to Flightradar24.

Hong Kong’s weather agency issued the black rain warning just before 6am on Aug 5 for a record-breaking fourth time in one week.

It followed a similar alert late on Aug 4 that lasted for a few hours.

The downpour flooded some roads and at least 18 landslides have been reported citywide, according to government data.

That includes Po Shan Road in the high-end Mid-Levels neighbourhood on Hong Kong Island, the site of a deadly landslide in June 1972 that killed 67 people.

That disaster led to the local government revamping and strengthening its slope management efforts.

Some metro exits were shut earlier in the morning, local media reported, and the judiciary said all court hearings will be adjourned.

The open-outcry market at the Hong Kong Gold Exchange will also be closed for the day. 

The weather agency issues a black rainstorm warning signal when heavy rain exceeding 70mm in an hour has fallen or is expected to drop.

The second-highest is red, followed by amber.

The back-to-back rainstorms of recent weeks can saturate soil and raise groundwater beyond normal levels, according to engineering geologist Stuart Millis, an associate director at consultancy Arup.

“You are having one black rainstorm, then two, three days later, you are having another red rainstorm, followed a couple of days later by another black rainstorm,” he said in an interview. “It’s that cumulative impact that causes concern from a geotechnical perspective.”

The torrential downpour comes on the heels of consecutive days of heavy rain, and is a sharp departure from an unusually dry first half of the year, which saw less than half the usual amount, according to the Hong Kong Observatory.

Neighbouring Shenzhen issued a citywide red alert at 4am on the morning of Aug 5, the first of its kind since 2018, according to a local media report.

Parts of mainland China have been lashed by extreme weather over the past week, including Shanghai, along with deadly flooding in Beijing.

‘Hit the gym’

Hong Kong’s most notable black rain event was in September 2023, with the alert remaining in place for an unprecedented 16 hours and the deluge breaking the one-hour, two-hour and 12-hour rainfall records.

About 606mm was recorded over a 12-hour period, the most since records began in 1884.

The storm swamped streets and flooded a metro station, leading to insurance claims of around HK$1.5 billion (S$246 million).

Still, not all are fazed by the rain. For Mr Ruchir Desai, a fund manager at Asia Frontier Capital in Hong Kong, earnings season does not pause for storm signals – nor does the daily commute.

“I’ve been in Hong Kong for 14 years and know how to navigate my way to work in this weather,” he said. “I will hit the gym later today once the signal is lifted.” Bloomberg