3.3 Severe Typhoon Mujigae (1522) : 1 – 5 October 2015
Mujigae was the third tropical cyclone necessitating the issuance of tropical cyclone warning signals by the Hong Kong Observatory in 2015.
Mujigae formed as a tropical depression over the sea areas east of the Philippines about 290 km east of Manila on the afternoon of 1 October and tracked west-northwestwards in the direction of Luzon. Mujigae entered the South China Sea the next morning and intensified into a tropical storm. Moving west-northwestwards steadily, it edged closer to western Guangdong and continued to intensify in the next two days. Mujigae developed into a severe typhoon in the small hours of 4 October, reaching its peak intensity before noon with an estimated sustained wind of 175 km/h near its centre. It made landfall near Zhanjiang in Guangdong that afternoon and weakened gradually. Mujigae finally degenerated into an area of low pressure on the afternoon of 5 October over Guangxi.
According to press reports, at least 4.6 million people were affected and 8 500 houses were damaged in Guangdong and Guangxi during the passage of Mujigae, with direct economic loss amounting to over 12 billion RMB. Under the influence of the circulation of Mujigae, Shunde district in Foshan and Panyu district in Guangzhou were affected by tornadoes, resulting in at least six deaths and over 200 injuries. Houses were damaged and vehicles were overturned. In Macao, there were numerous reports of fallen trees and incidents of blown down objects, with flooding in low-lying areas. A vessel ran aground about 210 km west of Hong Kong and all 14 crew members on board were rescued.
As Mujigae gradually edged closer to the coast of Guangdong, the Standby Signal No. 1 was issued at 8:40 p.m. on 2 October when Mujigae was about 670 km south-southeast of Hong Kong. As it continued to move closer to the territory, the Strong Wind Signal No. 3 was issued at 10:20 a.m. on 3 October when Mujigae was about 410 km south-southeast of Hong Kong. East to northeasterly winds strengthened significantly over Hong Kong in the afternoon, becoming generally strong and occasionally reaching gale force offshore and on high ground. At the Hong Kong Observatory Headquarters, the lowest instantaneous mean sea-level pressure of 1009.7 hPa was recorded at 3:37 p.m. on 3 October when Mujigae was about 370 km to the south. Mujigae came closest to the territory around 9 p.m. that night, skirting past around 320 km south-southwest of Hong Kong. Local winds remained generally strong from the east to southeast with occasional gales offshore and on high ground during the night and the next morning.
With Mujigae moving inland and weakening gradually on the afternoon of 4 October, local winds started to subside gradually. The Strong Wind Signal No. 3 was replaced by the Standby Signal No. 1 at 8:40 p.m. on 4 October. Although Mujigae further weakened and moved away from Hong Kong, winds were still strong offshore and on high ground under the combined effect of Mujigae and a ridge of high pressure along the coast of southeastern China. The Strong Monsoon Signal replaced the Standby Signal No. 1 at 5:20 a.m. on 5 October and lasted till 3:30 p.m. that day.
Under the influence of Mujigae, a maximum sea level (above chart datum) of 3.08 m and a maximum storm surge of 0.64 m (above astronomical tide) were recorded at Tsim Bei Tsui.
There were sunny periods and a few showers in Hong Kong on 2 October. Under the influence of the rainbands associated with Mujigae, local weather started to deteriorate with squally showers in the afternoon on 3 October. The weather remained cloudy to overcast with occasional heavy squally showers and thunderstorms in the following two days. The Amber Rainstorm Warning Signals were issued twice on 3 and 4 October. More than 150 millimetres of rainfall were generally recorded during the four-day period from 2 to 5 October. Rainfall over the southwestern part of Lantau Island even exceeded 250 millimetres.
In Hong Kong, at least 30 trees were blown down and 14 incidents of flooding were reported during the passage of Mujigae. Overhead cables near Fanling train station were affected by a fallen tree, resulting in a disruption of train services. At the Hong Kong International Airport, 39 aircraft were diverted.
Information on the maximum wind, period of strong force winds, daily rainfall and maximum sea level reached in Hong Kong during the passage of Mujigae is given in Tables 3.3.1 - 3.3.4 respectively. Figures 3.3.1 - 3.3.4 show respectively the track of Mujigae, the rainfall distribution for Hong Kong, a satellite imagery and a radar imagery of Mujigae.
