ENG-1987 — Page 345

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THE ENVIRONMENT

January 1987 had plenty of sunshine and was relatively warm. The monthly mean temperature of 17.3°C was 1.7°C above normal. Warm conditions during the month were directly linked to the ample sunshine, which was 19 per cent above mean.

Almost balmy conditions continued into February. In fact, the month's mean tempera- ture of 18.3°C was the third warmest on record while the mean temperature for the first two month of the year, 17.8°C, was the second highest.

March was a month of record-breaking weather events. Besides being the warmest March on record, with a monthly mean temperature of 21.3°C, it was very wet, with a total rainfall of 234.0 millimetres, more than four times the normal amount. Violent thunder- storms from March 16 to 18 brought 194.7 millimetres of rainfall, the highest recorded for three-day period in March. Rain was heaviest on March 17, and both the daily rainfall of 126.4 millimetres and the hourly rainfall of 50.1 millimetres between 9 and 10 a.m. set new records for March. The torrential downpour resulted in 116 cases of flooding and four cases of minor mudslips throughout the territory. On March 18, hail was reported in Sai Kung, Sha Tin and the northern part of Kowloon between 8.00 and 8.45 a.m.

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April continued to be wetter than usual. Monthly total rainfall of 277.8 millimetres was about twice the normal. Squally thunderstorms on April 5 affected Hong Kong and hail was reported in Sha Tin and Lai Chi Kok around 5 p.m. Persistent heavy rain on April 6 resulted in 133 cases of flooding and nine cases of landslips. Some 100 hectares of farmland were inundated in Yuen Long, Tuen Mun and Tai Po. Over 5 000 head of livestock were drowned. A significant surge of the winter monsoon arrived in Hong Kong on the morning of April 12 and flashes of lightning killed a fisherman and struck two others in Sai Kung that morning.

Frequent encounters between the moisture-laden southwest monsoon and cooler air from the north maintained the wet and overcast weather in May. The total duration of sunshine for the month was 102.8 hours, only two thirds of the normal, and the month's total rainfall of 460.2 millimetres, 54 per cent above normal. Thunderstorms were prevalent, occurring on 12 days during May. A waterspout was reported off the waters of Lai Chi Kok near Mei Foo Sun Chuen at about 1.30 p.m. on May 16. This waterspout might have been responsible for sinking a fishing boat, injuring two people. In Kennedy Town, seven wooden huts were destroyed by fire after being struck by lightning. Minor landslips occurred in Kwai Chung and Mt. Nicholson. Intense thunderstorms again battered the territory on May 22 and 23 causing 66 cases of flooding throughout the territory and at least six cases of minor landslips.

June was drier than usual. However, as early season rain had been plentiful, cumulative rainfall from January to June was still some 24 per cent above the half year norm. Tropical Cyclone Warning Signals were hoisted for the first time. That was during the approach of Tropical Storm Ruth on June 18.

July was characterised by a showery start, a mid-month dry spell and by the episode of torrential rain between July 22 and 30 when frequent thunderstorms occurred for nine consecutive days. During this period, there were 88 reports of flooding and 46 reports of landslips throughout the territory. About 120 hectares of farmland and three hectares of fish ponds were inundated. The most serious landslip occurred near Cho Yiu Chuen in Kwai Chung on July 30, where more than 1 000 residents had to be evacuated.

Rainfall in August was 57 per cent below normal, and the duration of sunshine was the sixth longest on record for the month. Atmospheric pressure over South China was abnormally high and the local mean sea-level pressure was the highest on record for August. Because of Betty and Cary, the Stand-by Signal No. 1 had to be hoisted for the

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