Overview of Tropical Cyclone in June 2021

Three tropical cyclones occurred over the western North Pacific and the South China Sea in June 2021. Koguma was also the first tropical cyclone necessitated the issuance of the tropical cyclone warning signals by the Observatory this year.

Choi-wan formed as a tropical depression over the western North Pacific about 1 700 km east-southeast of Manila on the morning of 30 May and moved west-northwestwards. It intensified into a tropical storm the next day and moved across the seas east of the Philippines. Choi-wan reached its peak intensity with an estimated maximum sustained wind of 75 km/h near its centre in the small hours on 1 June. It moved across the Philippines afterwards and entered the South China Sea. Choi-wan turned to move northwards on 3 June and weakened gradually. It then moved northeastwards on 4 June and finally evolved into an extratropical cyclone over the vicinity of the Ryukyu Islands in the small hours on 5 June.

According to press reports, Choi-wan left at least 11 deaths, 3 injuries and 2 missing in the Philippines during its passage. Near 94 000 people were affected. Choi-wan also brought torrential rain and flooding to Taiwan. Electricity supply to around 50 000 households was interrupted in Taibei.

A monsoon depression developed into a tropical depression over the northern part of the South China Sea about 500 km south-southwest of Hong Kong on the afternoon of 11 June. It generally tracked west-northwestward towards Hainan Island. The tropical depression moved across Hainan Island on the morning of 12 June and was named Koguma in the afternoon. Koguma intensified into a tropical storm over Beibu Wan in that evening and reached its peak intensity with an estimated maximum sustained wind of 65 km/h near its centre. It made landfall over the northern part of Vietnam on the morning of 13 June and degenerated into an area of low pressure over inland Vietnam in the afternoon.

According to press reports, Koguma left at least 1 death and 2 missing during its passage to Vietnam. At least 130 houses were collapsed. For detailed information of Koguma including its impact to Hong Kong, please refer to the Tropical Cyclone Report of Koguma.  

Champi formed as a tropical depression over the western North Pacific about 390 km east-southeast of Guam on the morning of 21 June. It generally moved northwestwards and intensified gradually. Champi intensified into a severe tropical storm in the small hours on 25 June and turned to move north or north-northeastwards. Champi further intensified into a typhoon that night and reached its peak intensity with an estimated maximum sustained wind of 120 km/h near its centre. Champi started to weaken afterwards and finally evolved into an extratropical cyclone over the seas east of Honshu, Japan on 27 June.