Report on Typhoon Saudel (2017)

Saudel was the fifth tropical cyclone affecting Hong Kong in 2020.

Saudel formed as a tropical depression over the western North Pacific about 920 km east of Manila on the morning of 19 October. Saudel moved generally west-northwestwards and intensified gradually. It moved across Luzon on the night of 20 October and entered the central part of the South China Sea in the next morning. Saudel turned to move northwestwards during the day. It intensified into a typhoon on 22 October and reached its peak intensity the next day with an estimated sustained wind of 140 km/h near its centre. Affected by the dry northeast monsoon, Saudel then turned to track westwards and weakened gradually. It finally degenerated into an area of low pressure over the seas east of central Vietnam on the night of 25 October.

According to press reports, over 6000 people were evacuated because of flooding and landslips in the Philippines during the passage of Saudel.

In Hong Kong, the Standby Signal No.1 was issued at 5:40 p.m. on 22 October when Saudel was about 600 km south-southeast of the territory. The lowest instantaneous mean sea-level pressure of 1009.1 hPa was recorded at the Observatory headquarters at that time. As Saudel edged closer towards the south China coast, the Strong Wind Signal No. 3 was issued at 12:20 a.m. on 23 October when Saudel was about 570 km south-southeast of Hong Kong. Under the combined effect of Saudel and the northeast monsoon, local winds were generally fresh north to northeasterlies and occasionally reached strong force offshore and on high ground at the night of 22 October and on 23 October. Gale force winds also affected high ground at times on 23 October. Saudel came closest to the territory at around 8 p.m. on 23 October as it skirted past about 490 km south of Hong Kong. As Saudel departed from Hong Kong and weakened, its direct threat to Hong Kong diminished and all tropical cyclone warning signals were cancelled at 9:10 a.m. on 24 October. Under the influence of the northeast monsoon, strong winds still affected offshore at times with occasional gale force winds on high ground. The Observatory issued the Strong Monsoon Signal immediately afterwards and the signal lasted till 1:00 p.m. the following day.

During the passage of Saudel, a maximum sea level (above chart datum) of 2.90 m was recorded at Tsim Bei Tsui and a maximum storm surge (above astronomical tide) of 0.67 m was recorded at Tai Po Kau.

Saudel did not cause significant damage in Hong Kong. Affected by the cloud bands associated with Saudel and a dry northeast monsoon, local weather turned cloudier, slightly cooler and remained dry on 23 – 24 October.