Revamp of typhoon warnings considered

PUBLISHED : Friday, 13 October, 2006, 12:00am
UPDATED : Friday, 13 October, 2006, 12:00am

Observatory floats three options after chaos caused by Prapiroon in August


The Hong Kong Observatory has come up with three possible ways to improve the city's typhoon signal system following the chaos caused by Typhoon Prapiroon in August.


Officials are considering adding more typhoon signals, having district-based signals or increasing the wind-speed reference points to overhaul the current system which is 30 years old.


They said a new signal system that deviates significantly from existing methods might incur huge social costs since it would affect almost every aspect of the city.


The review came after Typhoon Prapiroon blew past Hong Kong in August, toppling containers, uprooting trees and grounding many flights at the airport. The typhoon signal No8 was never hoisted because the average wind speed in Victoria Harbour did not reach 63km/h - the speed needed to trigger the signal.


Among the three preliminary options floated so far, officials hinted that a district-based signal system was unlikely to be adopted as it would lead to confusion among the public, especially people travelling between districts.


While a new typhoon signal No5 could be inserted between the current typhoon signal No3 and typhoon signal No8 to warn the public that stronger winds are expected, officials believe it would take a long time for people to adjust to the new signal.


Officials said that typhoon signal No5 existed before the 1970s, but was cancelled in a bid to simplify the system. Currently, there are typhoon signals 1, 3, 8, 9 and 10. When typhoon signal No8 is hoisted, offices and schools are closed.


The final option would be to refine the existing system without changing the signals. More wind-speed data from stations in urban or outlying areas might be taken into account rather than use the wind speed in Victoria Harbour as the key parameter for hosting typhoon signal No8. The extra data could be weighted for significance, reflecting the risk to people in different areas.


The Observatory has also been considering revamping its weather monitoring stations so that each district has a 'representative' station to track local weather changes.


Hong Kong Observatory director Lam Chiu-ying said there was no simple or perfect solution to address all the concerns of the public.


'We must bear in mind that a single signal will never resolve all problems. And, no matter how you change the system, the possibility remains that the Observatory could make a wrong forecast,' he said.


A consultation on the review involving key stakeholders - labour groups, government departments, media and the business community - has been ongoing for a month.


Poon Siu-ping, a member of the Labour Advisory Board, said he did not support any district-based signal system. 'Whatever the new system is, the Observatory must upgrade its forecast skills to protect people working outdoors,' he said.