The cold hard factsTop News | Kenneth Lau, Yupina Ng and Mary Ann Benitez 26 Jan 2016
The forecasting accuracy of the Hong Kong Observatory was called into question a day after Hong Kong shivered through the coldest day in 59 years.
A total of 129 people were taken to places of safety and 67 sent to hospital from Tai Mo Shan for hypothermia.The observatory's original forecast for Sunday's low was six degrees Celsius but the actual temperature recorded was three degrees. Subzero temperatures were recorded at the highest point of Tai Mo Shan and other peaks.
Rescuers yesterday described a rare and sudden change in weather conditions on Tai Mo Shan on Sunday brought about by a Typhoon-3 force monsoon and compounded by rain. The road was covered by a centimeter of ice.
The police commander for Tsuen Wan, Kwok Ho-yee, said the cold weather that was seen on Sunday was the first in decades and attracted a large number of frost chasers. "In future if there is a similar incident we will probably make public announcements as early as practicable," Kwok said yesterday.
At 11.45pm on Saturday, the observatory said in its forecast: "It will be very cold. Temperatures over the urban areas will fall gradually from around eight degrees at first to about six degrees later."
A New Zealand weather website, which adopted the European Severe Weather Database, had forecast that Hong Kong's temperature would drop to four degrees on Sunday and it would have one centimeter of snow.
The European Centre for Medium- Range Weather Forecasts also forecast two to five degrees.
Senior scientific officer Chan Sai- tick admitted yesterday that there was uncertainty in the nine-day weather forecast system. "The actual temperature was lower than we expected mainly because of the longer period of rain," he said. "Currently, our system could not forecast how long the rain would take, and the extreme weather has made the forecast become more difficult," he said.
Chan said the observatory has always taken computer models from the United States, Japan and the Europe and it tried to find a balance. "Taking the most extreme one is not a smart option, although it might be eye-catching for the public," he added.
However, the observatory was quoted as saying "we know best" when telling the public not to worry and not to believe other weather websites that forecast there would be snow in Hong Kong.
Among the 129 rescued were 62 sick runners in the Hong Kong 100 Ultra Marathon. Three were in serious condition. The rescue operation lasted 19 hours - from 5.35am on Sunday to 12.30am yesterday. The rescuers described awful conditions, with the most difficult at M143 checkpoint at about 2pm when the weather and wind was at its worst, said acting divisional commander (New Territories South) of Fire Services, Wong Ka-wing. "The gradient was 40 to 45 degrees and the road surface was all iced over so colleagues had to move in a zigzag manner to reach those seeking assistance," Wong added.
Chief pilot (operations) of the Government Flying Service, Wu Wai- hung, said no civilian or military helicopter is certified to operate at zero Celsius temperatures.
"The monsoon was very strong near Tai Mo Shan," he said. "We are talking about 50 nautical miles an hour, equivalent of a Typhoon 3 gale, and ice rain."
Assistant Director (New Territories) of Fire Services Yau Wai-keung said 56 pairs of crampons had to be sent for rescues.
The ice on the road was a centimeter thick. "Our boots can only handle two millimeter-thick layers," he said.