Tropical Cyclones in 2018 > Tropical Storm Ewiniar (1804): 2 – 8 June 2018

3.1 Tropical Storm Ewiniar (1804): 2 – 8 June 2018

Ewiniar was the first tropical cyclone affecting Hong Kong in 2018.

Ewiniar formed as a tropical depression over the southern part of the South China Sea about 510 km south of Xisha on the night of 2 June and moved north-northwestwards. Ewiniar turned to move north to north-northeastwards on 4 June and skirted past the sea areas east of Hainan Island the next day. Slowing down and intensifying into a tropical storm on 6 June, it lingered and made a loop east of Leizhou Peninsula and the northeastern part of Hainan Island. Ewiniar reached its peak intensity with an estimated sustained wind of 75 km/h near its centre on the morning of 7 June and started to move steadily north-northeastwards, making landfall near Yangjiang across the coast of western Guangdong that night. It weakened gradually and finally degenerated into an area of low pressure over the inland areas of Guangdong on the night of 8 June.

According to press reports, Ewiniar brought torrential rain to Hainan, Guangdong, Guangxi, Fujian and Hunan, with flooding and landslides reported in many places. At least five people were killed and over 210 000 people were affected.

In Hong Kong, the No. 1 Standby Signal was issued at 11:20 a.m. on 5 June when Ewiniar was about 590 km south-southwest of the territory. Local winds were moderate to fresh east to southeasterlies on 5 and 6 June, occasionally strong offshore and on high ground. With Ewiniar edging closer to Hong Kong, the No. 3 Strong Wind Signal was issued at 12:40 p.m. on 7 June when Ewiniar was about 330 km west-southwest of Hong Kong. Local winds became generally fresh to strong southeasterly in the afternoon, occasionally reaching gale force on high ground. Ewiniar came closest to Hong Kong around 1 p.m. on 8 June with its centre about 200 km west-northwest of Hong Kong. With Ewiniar weakening and local winds subsiding gradually, the No. 3 Strong Wind Signal was replaced by the No. 1 Standby Signal at 3:40 p.m. on 8 June, and all tropical cyclone warning signals were cancelled at 6:20 p.m. that evening.

During the passage of Ewiniar, a maximum sea level (above chart datum) of 2.52 m and a maximum storm surge (above astronomical tide) of 0.68 m were recorded at Tsim Bei Tsui. The lowest instantaneous mean sea-level pressure of 998.7 hPa was recorded at the Observatory headquarters at 5:01 p.m. on 8 June when Ewiniar was about 200 km west-northwest of Hong Kong.

Ewiniar brought episodes of heavy rain and squalls to Hong Kong during 5 – 8 June. Overall, more than 250 millimetres of rainfall were generally recorded over the territory, with rainfall over the northeastern part of the New Territories exceeding 400 millimetres. The rainstorm shortly after noon time on 6 June led to the issuance of the first Amber Rainstorm Warning this year. There were more outbreaks of heavy rain the next morning, especially at Sha Tin and Tai Po, and waterspout was spotted at Cheung Chau that evening. The heavy downpour on the morning of 8 June necessitated the issuance of the Red Rainstorm Warning by the Observatory.

In Hong Kong, there were reports of fallen trees, flooding and landslide during the passage of Ewiniar. A tree collapsed in Sai Wan Ho, damaging two vans passing by and one of the drivers suffered a minor injury. A private car in Tai Wai and a minibus in Pokfulam were also damaged by toppled trees. A number of roads were blocked due to flooding or fallen trees, resulting in disruption of traffic.