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GEOGRAPHY AND CLIMATE
tragic event was, however, the capsize of the Hong Kong-Macau ferry, SS Fat Shan, near the north-eastern tip of Lantau with the loss of all but four of her crew of 92.
During the first half of September, troughs of low pressure domi- nated the south China coastal area and a total of 120 mm of rainfall was recorded at the Royal Observatory. On September 19, an early arrival of the winter monsoon brought strong northerly winds and cooler weather to the Colony. Temperatures at the Royal Observa- tory fell to a minimum of 21.6°C on September 21. Typhoon Delia passed about 190 miles south of Hong Kong on a westerly course on September 28 and caused a few hours of strong winds.
During October, a persistent anticyclone was centred over China and, with only a few interruptions, maintained a steady winter monsoon along the south China coast. The Strong Monsoon Signal was hoisted on three occasions during the month. The last tropical cyclone to affect Hong Kong in 1971 was typhoon Elaine, which came within 300 miles of the Colony on October 7 and produced strong winds in exposed places.
Abnormally high tides were experienced from October 5-10 and some flooding occurred at Tai O, Victoria and Quarry Bay during the night of October 7-8. The tide level was generally about one metre higher than normal. Local fishermen reported that they had not observed such a phenomenon in the past 20 years.-This was probably caused by an unusual movement of ocean currents in the Pacific as high tides were also recorded in Japan around the same time.
17
November was exceptionally, dry with only a trace of rainfall recorded at the Royal Observatory. Only on one previous occasion, in 1924, had such a small amount of rainfall been recorded in November. The mean relative humidity of the month, 58 per cent, and the minimum hourly relative humidity of 17 per cent at 3 p.m. on November 17 were both the lowest on record for November. The Strong Monsoon Signal was hoisted on two occasions.
The fine and dry weather persisted into mid-December and there were long periods of sunshine on almost every day. However, an active upper-air disturbance developed over west China on December 16 and caused widespread heavy rain. Weather in Hong Kong became dull and rainy during the next 10 days and, as a result, the month became the wettest December since 1884. The rainfall of 97.8 mm on December 18 was a new daily record for the month.