ENG-1976 — Page 277

THE ENVIRONMENT

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The severe weather phenomena which can affect Hong Kong include tropical cyclones between May and November, strong monsoon winds mostly between October and March, frost and ice on hills and inland in the New Territories between December and February, and thunderstorms. Waterspouts and hailstorms are comparatively rare. Strong monsoon winds usually occur in the winter during outbreaks of cold air, although strong southwest monsoon winds are not unknown. The lowest air temperature recorded at the Royal Observatory in Kowloon is 0.0°C, although lower temperatures have been recorded in the New Territories. Thunderstorms may occur at any time of the year but are most frequent between May and August when they occur on about five days in each month.

Tropical cyclones occur in Southeast Asia throughout the year but have never caused gales in Hong Kong between December and April. Normally about five tropical cyclones cause strong winds in Hong Kong each year and they are most common between July and September. About one tropical cyclone a year causes gales. Tropical cyclones usually bring fine and very hot weather when centred near the Philippine Islands, but if they come closer to Hong Kong they bring winds and rain which is heavy and widespread. The severe weather associated with a tropical cyclone usually affects Hong Kong for one to three days.

The Year's Weather

Although exceptionally dry conditions prevailed during the first five months, 1976 was the fifth consecutive year with above average rainfall. The yearly total was 2 197.2 mm-of which nearly 75 per cent was recorded in the three months of June, July and August. Most of the year was warmer and less humid than usual.

There were 27 tropical cyclones reported over the western North Pacific and the South China Sea, and tropical cyclone warning signals were displayed on five occasions in Hong Kong. Typhoon Iris in September was the only tropical cyclone that caused sustained gales in Hong Kong and damage to property was slight. In contrast, the exceptionally heavy rain and violent thunderstorms that developed in the wake of tropical storm Ellen in August caused widespread flooding and disastrous landslips in many places. Eighteen people were killed in the landslip at the Sau Mau Ping housing estate, while another 12 lost their lives in other incidents.

The first two months of the year were warm, sunny and dry. Although fire danger warnings were issued, numerous fires broke out in the urban areas and large areas of the New Territories were blackened by hill fires. Between February 14 and 18 there was widespread fog over Hong Kong waters and along the south China coast, and as a result one ship went aground at Lei Yue Mun Channel and four others were involved in collisions.

The next three months were generally cloudy with widespread fog on many days in March and April, but no serious accidents were reported at sea. Typhoon Olga remained almost stationary near Luzon from May 21-5, and the fine weather ahead of it gave rise to unusually high temperatures in Hong Kong. On May 26 the Royal Observatory recorded a maximum temperature of 35.2°C, which was the highest in the year and the second highest on record for any May.