Let's open our eyes to false alarms - and real dangers - of typhoons

PUBLISHED : Sunday, 26 August, 2007, 12:00am
UPDATED : Sunday, 26 August, 2007, 12:00am

I refer to the comments made by the director of the Observatory, Lam Chiu-ying ('Observatory wants an end to herd mentality', August 18, and 'Storm alert system out of date: Observatory chief', August 19).

It indeed seems unnecessary to shut down Hong Kong when the No8 signal is hoisted and only gales or storm force winds are anticipated.

However, if a direct hit by a typhoon - especially a powerful typhoon - seems likely, it could surely prove foolhardy to continue with business as usual.

Reports on two powerful storms last century give some indication of the danger typhoons pose. An unnamed storm in 1937 killed about 11,000 people (largely from the storm surge) with little or no warning, and forced ships aground. The sea reached Des Voeux Road in Central, and fish were found to have been blown 'many yards from the sea on to buildings 90 feet [27 metres] above the ground', according to one report. Typhoon Wanda, in 1962, killed 130 people despite advance warnings; the sea reached the tracks at Sha Tin station.

Accounts of hurricanes such as Andrew also suggest a major typhoon could severely affect even our modern buildings. An architect friend tests glass panels for resistance to typhoon-strength winds, but the tests don't involve projectiles. Objects carried by winds in a strong typhoon could surely damage even the strongest glass walls facing Victoria Harbour - and result in mayhem if people were trying to keep working.

Mr Lam noted that our tropical cyclone warning system is antiquated. It seems especially out of date in one respect: we have no categories for typhoons. It would surely be advisable to introduce categories like those applied in the United States under the Saffir-Simpson Scale. It ranks hurricanes from Category 1 to 5: Category 5 storms are rare but potentially catastrophic.

The US scale is now widely reported in the news: Hurricane Dean in the Gulf of Mexico reached Category 5. So surely there is a strong case for adopting exactly the same scale - and reporting wind speeds in one-minute averages, rather than the 10-minute averages that we have traditionally used for typhoons.

Martin Williams, director, Hong Kong Outdoors