Warning system should let individuals use judgment

The director of the Hong Kong Observatory has chosen to speak out while the topic is hot about the case for the city's time-honoured response to typhoons. Like many others including this newspaper, Lam Chiu-ying has questioned the need for an automatic mass evacuation of the city after the No 8 signal was hoisted.

When the signal was raised on August 10, the rush to go home prompted traffic chaos and delays and commercial disruption. And then Tropical Storm Pabuk passed by with not a single flight cancelled and few incidents related to wind and rain.

It would be foolhardy and irresponsible to assume from this one instance or similar incidents in the recent past that we can lower our guard against typhoons. This weekend provides a reminder of that, with Typhoon Sepat unleashing its destructive and life-threatening fury on Taiwan and Fujian.

We can never relax our vigilance or overlook any opportunity to sharpen it. In fact, the Observatory recently revamped its typhoon warning system to give better coverage of localised violent weather across Hong Kong. As a result we may expect more No 8 signals over time. That said, the views of the official responsible for the system on the appropriate response in this day and age are worth some weight.

In a letter to the South China Morning Post published yesterday, he revealed that he wrote to Hong Kong Exchanges and Clearing a few years ago advocating that the stock market should continue operating in the cyber world even if the No 8 signal is up. But the exchange refused, fearing that a smaller volume of transactions during a typhoon might open the market to manipulation.

That sounds a credible reason. But one wonders if the exchange was just reluctant to risk incurring the wrath of many sectors by breaking a long-standing practice of pulling the plug on its electronic operations in response to a very strong wind-warning signal, even though it was originally designed for mariners.

Certainly, in times past when such winds blew, the junks and sampans had to seek refuge in the typhoon shelters. Over the years the public adopted the system. When Hong Kong was much less developed, with many substandard buildings and dwellings more exposed to the elements, it made sense to rush home and batten down the hatches. Moreover, the heavy rain that accompanies typhoons led to flooding, landslides and blocked roads, resulting in hazard to life and limb.

But Hong Kong people have since become far less vulnerable to inclement weather. Today, the buildings in which we live and work are built to withstand even a direct hit by a typhoon. And we can safely travel on a rail system that can operate at all times except the very worst conditions. Most slopes have been stabilised.

For all its advances in technology and equipment, weather forecasting remains an imprecise science. But there is an argument for considering a more flexible threshold at which people leave the city en masse and head home in response to a typhoon warning.

Perhaps we could adopt precautions more appropriate to the expected effect of a typhoon, if not expecting a direct hit or a prolonged alert. Only people who really feel the need to go home would do so, instead of everyone effectively being left with nowhere else to go. The rest could be kept updated with information enabling them to make an informed decision whether to remain at work or school or head home in a manner as orderly as possible.