TROPICAL CYCLONES IN 2009
| 3.4 | Typhoon Molave (0906): 15 - 19 July 2009 |
Molave was the fourth tropical cyclone that necessitated the issuance of a tropical cyclone warning signal in Hong Kong in 2009. During its passage, the Hong Kong Observatory issued the Increasing Gale or Storm Signal No. 9, the first No. 9 signal since Typhoon Nuri in August 2008.
Tropical Depression Molave formed over the western North Pacific about 670 km east of Manila on 15 July and moved generally northwestwards. It intensified into a tropical storm the next day. While crossing the Luzon Strait on 17 July, Molave strengthened into a severe tropical storm in the afternoon. Molave entered the South China Sea and turned to move west-northwestwards that night. It intensified into a typhoon on the morning of 18 July and moved towards the south China coast at an average speed of over 20 km/h. Molave reached its peak intensity with estimated maximum winds of 140 km/h near its centre that night. In the early hours of 19 July, Molave made landfall over the coastal areas of Dapeng Peninsula, then moved across Mirs Bay and Shenzhen and weakened into a severe tropical storm. Molave entered western Guangdong in the morning and weakened into a tropical storm. It weakened further into a tropical depression that afternoon and subsequently into an area of low pressure over Guangxi at night. According to press reports, five people were killed in the Philippines during the passage of Molave. In Guangdong, over 240 000 people were affected, over 1 500 hectares of farmland were damaged, over 80 houses collapsed and the direct economic losses were around 200 million yuan. In Shenzhen, two people were missing and widespread flooding was reported. Around 100 flights were cancelled or delayed at Shenzhen Airport. Three vessels lost power in rough seas off Shantou and 23 sailors on board were rescued. A fishing vessel sank in the coastal waters of Wenzhou, Zhejiang and two people on board were missing.
In Hong Kong, the Standby Signal No. 1 was issued at 10:15 p.m. on 17 July when Molave was about 680 km east-southeast of Hong Kong. Local winds were mainly light to moderate west to northwesterlies. As Molave was expected to approach Hong Kong rapidly, the Strong Wind Signal No. 3 was issued at 2:15 p.m. on 18 July when Molave was about 310 km to the east of Hong Kong. Local winds freshened from the northwest and strengthened gradually. They became generally strong, reaching gale force on high ground towards midnight. The No. 8 Northwest Gale or Storm Signal was issued at 11:30 p.m. when Molave was about 100 km east of the Hong Kong Observatory. Winds strengthened significantly in the early hours of 19 July. Gale force winds from the west to northwest generally affected Hong Kong, reaching storm force offshore and on high grounds. The Increasing Gale or Storm Signal No. 9 was issued at 1:30 a.m. on 19 July. Molave was closest to Hong Kong between about 2 a.m. and 3 a.m. when it passed about 40 km to the north-northeast of the Hong Kong Observatory. Molave started to move away from Hong Kong thereafter and local winds changed to gale force southwesterlies, reaching storm force offshore and on high ground. The No. 8 Southwest Gale or Storm Signal was issued at 4:40 a.m. Gales gradually subsided around dawn and the Strong Wind Signal No. 3 was issued at 6:40 a.m., followed by the Standby Signal No. 1 at 10:40 a.m. As Molave continued to move further away from Hong Kong and weakened, local winds gradually moderated. All tropical cyclone warning signals were cancelled at 1:15 p.m. that day. The maximum winds recorded at various stations and the periods of strong and gale force winds during the passage of Molave are given in Tables 3.4.1 and 3.4.2 respectively.
During the passage of Molave, the lowest instantaneous mean sea-level pressures recorded at some selected stations are as follows:-
Station |
Lowest instantaneous mean sea-level pressure |
Date/Month |
First and last time recorded |
Hong Kong Observatory Headquarters |
985.6 hPa |
19/7 |
1:52 - 1:58 a.m. |
Ta Kwu Ling |
977.2 hPa |
19/7 |
2:23 - 2:24 a.m. |
Sha Tin |
982.6 hPa |
19/7 |
1:55 a.m. |
Waglan Island |
985.5 hPa |
19/7 |
1:17 a.m. |
The weather in Hong Kong was sunny and very hot on 17 and 18 July. There was some haze on 18 July. Under the influence of the outer rainbands of Molave, squally showers and a few thunderstorms affected Hong Kong that evening. Heavy rain with squalls affected Hong Kong on the morning of 19 July. The Amber and Red Rainstorm Warnings were issued at 1:45 a.m. and 2:25 a.m. respectively, while the Landslip Warning was issued at 3:00 a.m. The rain gradually eased off in the afternoon.
In Hong Kong, five people were injured during the passage of Molave. There were at least 425 reports of fallen trees and three reports of collapsed scaffolding. In Tai Po Tau, a 10-metre high tree toppled and damaged the roof of a dwelling nearby. No one was hurt in the incident. Six people in Yuen Long were forced to evacuate their wooden house after it was damaged by a fallen 14-metre tall tree. A 20-metre tree collapsed in Cloudy Hill, Kowloon, damaging the electric cables and the rooftop of a house and interrupting the electricity supply to seven households nearby. In Tai Po Lam Tsuen San Tsuen, a large tree fell on three to four private vehicles parked there. The windscreens of a bus and a lorry were smashed by a collapsing tree in Chai Wan and Tai Po respectively. No one was hurt in these incidents. A total of three yachts ran aground off the seas of Tai Po and Sai Kung. At the Hong Kong International Airport, 11 flights were cancelled, 31 flights were delayed and one flight was diverted.
Information on the daily rainfall and maximum sea level in Hong Kong during the passage of Molave is given in Tables 3.4.3 and 3.4.4 respectively. Figures 3.4.1 - 3.4.6 show respectively the track of Molave, the rainfall distribution for Hong Kong, time series of the pressure recorded at Ta Kwu Ling, time series of the wind speed recorded at Cheung Chau, a satellite and radar imagery of Molave.
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