THE TROPICAL CYCLONE WARNING SERVICE

Introduction: A tropical cyclone is one of the most destructive forces of nature. It is a huge rotating column of warm and moist air with a very low sea-level pressure near the centre. With wind speeds often exceeding 150 km/h and usually accompanied by torrential rain, a mature tropical cyclone can have its effects felt over a thousand kilometres away from its centre. Each year, an average of 30 tropical cyclones form over the northwest Pacific and the South China Sea. Of these, about one sixth come close to the south China coast and pose a threat to Hong Kong.