TROPICAL CYCLONES IN 2016

3.3 Typhoon Nida (1604): 29 July – 3 August 2016

Nida was the third tropical cyclone necessitating the issuance of tropical cyclone warning signals by the Hong Kong Observatory in 2016. It was also the first tropical cyclone requiring the issuance of Gale or Storm Wind Signal No. 8 in the year.

Nida formed as a tropical depression over the western North Pacific about 750 km east-southeast of Manila on the night of 29 July and moved north-northwestwards at first. Nida then took on a northwesterly track towards the Luzon Strait on the afternoon of 30 July and intensified gradually. After developing into a severe tropical storm on the morning of 31 July, it swept across the north coast of Luzon in the afternoon and entered the northeastern part of the South China Sea that night, taking on a west-northwesterly track towards the coast of Guangdong. It further intensified into a typhoon and reached its peak intensity on the afternoon of 1 August with an estimated sustained wind of 130 km/h near its centre. Nida made landfall near Dapeng Peninsula around 3 a.m. on 2 August and moved across Shenzhen, passing just to the north of Hong Kong. It continued to weaken as it moved further inland, before finally degenerating into an area of low pressure over Guangxi early in the morning of 3 August.

According to press reports, about 500 000 people were affected and more than 300 houses collapsed in Guangdong, Guangxi, Hunan, Guizhou and Yunnan during the passage of Nida, with direct economic loss exceeding 500 million RMB. Business and schools were suspended in seven cities of Guangdong. Transportation services were paralyzed. Electricity supply to more than 16 000 households was affected in Shenzhen.

The Standby Signal No. 1 was issued by the Hong Kong Observatory at 10:10 p.m. on 31 July when Nida was about 790 km east-southeast of the territory. Local winds were light to moderate from the northwest on the morning of 1 August. As Nida moved rapidly towards the coast of Guangdong, the Strong Wind Signal No. 3 was issued at 11:40 a.m. when it was about 440 km east-southeast of Hong Kong. Local winds started to strengthen significantly at dusk, becoming fresh north to northwesterly and strong on high ground. With Nida approaching the Pearl River delta region, the No. 8 Northwest Gale or Storm Signal was issued at 8:40 p.m. when it was about 200 km east-southeast of Hong Kong. Local winds strengthened further overnight and became strong to gale force from the west to northwest.

As Nida made landfall and skirted past just north of Hong Kong, local winds started to turn southwesterly and the No. 8 Southwest Gale or Storm Signal was issued at 4:40 a.m. on 2 August. Nida was closest to the territory around 5 a.m. when it was about 40 km north-northwest of the Hong Kong Observatory Headquarters. Southwesterly gales generally affected the territory near dawn with winds occasionally reaching storm force offshore and on high ground. With Nida moving inland and weakening in the morning, local winds subsided gradually during the day. The No. 8 Southwest Gale or Storm Signal was replaced by the Strong Wind Signal No. 3 at 12:40 p.m., and all tropical cyclone warning signals were cancelled at 5:10 p.m. later in the day.

Under the influence of Nida, maximum hourly mean winds of 47, 72 and 121 km/h and gusts of 112, 117 and 158 km/h were recorded at Star Ferry (Kowloon), the Hong Kong International Airport and Ngong Ping respectively. A maximum sea level (above chart datum) of 3.6 m and a maximum storm surge (above astronomical tide) of 0.9 m were recorded at Tsim Bei Tsui. The lowest instantaneous mean sea-level pressures recorded at some selected stations are as follows:-

Locally, there were sunny periods and haze during the day on 1 August. The rainbands of Nida brought heavy squally showers to Hong Kong that night and the next day. Amber Rainstorm Warning, Landslip Warning and Special Announcement on Flooding in the Northern New Territories were issued by the Observatory on the morning of 2 August. More than 100 millimetres of rainfall were generally recorded over the territory, and rainfall over Lantau Island even exceeded 200 millimetres.

In Hong Kong, at least 12 people were injured during the passage of Nida. There were more than 400 reports of fallen trees, two reports of flooding, one report of landslide and many incidents of falling objects. A satellite dish of around six feet was blown down to the pavement under strong winds in Sheung Wan. The scaffolding of a commercial building at Fleming Road in Wan Chai collapsed. A tree at Peacock Road in North Point fell down, damaging two private cars. Some trees also collapsed near Tin Yuet and Sam Shing Light Rail stations, resulting in a disruption of train services. A lamp post in Kwun Tong Bypass fell down under high winds. A barge rammed against the seafront under high waves in Tai Kok Tsui and a yacht ran aground in Sai Kung. Storm surge triggered by Nida caused minor flooding and backflow of sea water in some low lying areas in Lei Yue Mun, Tai O, Tuen Mun and Sai Wan. More than 320 hectares of farmland in the New Territories were affected. Around 500 flights were re-scheduled at the Hong Kong International Airport.

Information on the maximum wind, period of strong and gale force winds, daily rainfall and maximum sea level reached in Hong Kong during the passage of Nida is given in Tables 3.3.1 - 3.3.4 respectively. Figures 3.3.1 - 3.3.2 show respectively the track of Nida and the rainfall distribution for Hong Kong. Figure 3.3.3 shows the winds recorded at various stations in Hong Kong. Figures 3.3.4 – 3.3.5 show repectively trace of mean sea-level pressure recorded at the Hong Kong Observatory’s Headquarters and Ta Kwu Ling, and tide and storm surge recorded at Quarry Bay. Figures 3.3.6 – 3.3.7 show respectively a satellite imagery and a radar imagery of Nida. Some damages caused by Nida in Hong Kong are illustrated in Figures 3.3.8 – 3.3.11.