No 8 signal for Haima prompted by public safety concerns amid gales

PUBLISHED : Thursday, 03 November, 2016, 5:22pm
UPDATED : Thursday, 03 November, 2016, 10:46pm

I refer to the letter by Peter Lok (“Observatory’s response was over the top”, October 26) regarding the passage of Typhoon Haima on October 21.

I would first like to clarify the meaning of the tropical cyclone signal No 8 – it means gale- or storm-force wind is expected or blowing generally in Hong Kong near sea level. It does not mean winds reaching hurricane force, as suggested by your correspondent. Hurricane-force winds near sea level would require a No 10 signal.

Though Haima weakened after passing Luzon, it still maintained the strength of a typhoon with gales extending to a radius of some 200km.

Needless to say, when Haima landed just 110km east of Hong Kong, gale-force winds were to be expected in the territory and indeed gales were recorded in many places, including the Star Ferry, Central, North Point, Cheung Chau, Lau Fau Shan and Chek Lap Kok. Maximum gusts at some urban stations even reached storm force. Apart from more than 200 fallen trees, including two very big ones in Causeway Bay, there were also casualties during the passage of Haima, with one man dead and more than 10 people injured.

We share your correspondent’s concern about the disruption to air traffic due to Haima and, as such, frequent weather briefings on Haima were provided by the Observatory to the aviation community to facilitate its operational decision-making. We would like to clarify that no exact timing of signal changes (for example, “that the No 8 signal would be hoisted at 8am on Friday”) was mentioned. Your readers are advised to refer to the Observatory’s official announcements rather than rumours on the internet.

As Chek Lap Kok was consistently affected by cross winds of over 50km/h for several hours on October 21, flight operations at the airport were disrupted as a result. For the same reason, the Government Flying Service’s flight, originally planned to carry out meteorological measurements in the typhoon, had to be cancelled.

We would like to reiterate that the safety of the public is always the Observatory’s primary consideration in issuing tropical cyclone warning signals. With gales in many places around Hong Kong during the day on October 21, could members of the public, including our school kids, accept being exposed to such hazardous situations without a No 8 signal?

Cheng Cho-ming, assistant director, Hong Kong Observatory