ENG-1972 — Page 247

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THE ENVIRONMENT

these cyclones several times a year at varying distances from Hong Kong brings spells of bad weather with strong winds and heavy rain. Gales are experienced once a year on average, and less frequently the centre of a mature typhoon passes sufficiently close to Hong Kong to produce winds of hurricane force, endangering life and property.

The Year's Weather

During the year 1972, many countries in Asia suffered from widespread flooding caused either by tropical cyclones, as in Japan, or by heavy rain associated with the strong south-west monsoon, as in the Philippines. Hong Kong was no exception and the heavy rainstorm in June, which caused disastrous landslides and the collapse of several buildings, will probably be long remembered. Because of this tragedy, almost 150 people died and 20,000 people had to be rehoused.

In Hong Kong the year as a whole was slightly warmer, less cloudy, but much wetter than usual. It was the fourth wettest year since 1884, and the annual rainfall was more than 30 per cent higher than the normal value. Although five tropical cyclones affected Hong Kong during the year, only one, Typhoon Pamela, came sufficiently close to cause gales.

Apart from being slightly sunnier than usual, the weather during January was fairly normal. Although there was measurable rain on only three days, the total rainfall during the month was about 50 per cent above average.

Cold northerly winds affected Hong Kong at the beginning of the year, and the Strong Monsoon Signal was hoisted for eight hours on January 1. On January 23 and 24, widespread coastal fog was reported and, as a result, 39 aircraft were diverted from Hong Kong International Airport.

A very intense cold front passed through Hong Kong on February 4, and caused the air temperature to fall during the following five days. The minimum temperature recorded at the Royal Observatory on February 9 was 3.8°C, which was the third lowest temperature ever recorded in February. Frost warnings were issued on February 8 and 9, and ice was reported at Tate's Cairn. The coldest place, however, was on the top of Tai Mo Shan where a temperature of -6°C below freezing was recorded.

March was exceptionally fine and dry and several new records were established. The mean cloudiness of 49 per cent and the mean relative humidity of 73 per cent were the lowest, while the total sunshine of 188.6 hours was the highest ever recorded for the month. The monthly rainfall was also the second lowest on record for March.

April was a cloudy month with fog reported on several occasions. However, the foggy spells during the month were generally short-lived and did not seriously inter- rupt the air and sea traffic. The Strong Monsoon Signal was displayed from April 1 to 2, when Hong Kong was affected by a late winter monsoon surge.

The rainy season started in early May when a trough of low-pressure in the South China Sea brought moist air to Hong Kong. Rain was recorded on 27 days of the month with the total rainfall amounting to more than twice the normal value. The