Waterspout spotted in Hong Kong seas off Cheung Chau amid Tropical Storm Ewiniar

A waterspout was spotted in Hong Kong seas on Thursday amid the unstable weather brought by Tropical Storm Ewiniar.

A monitoring station on the island of Cheung Chau detected the natural phenomenon near Tung Wan beach at about 6.45pm.

Reports of sightings were also received, and images and video clips of the waterspout were widely circulated online.

Queenie Lam Ching-chi, a senior scientific officer with the Hong Kong Observatory, said data showed there had been a strong air convection – a prerequisite for the formation of a waterspout – at the site.

Waterspouts are fast-rotating air columns above water that extend down from the base of clouds, which in this case were part of rainbands brought by Ewiniar, Lam said.

Funnel clouds, a similar phenomenon, are rotating air columns not in contact with the ground or water.

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Both are most commonly seen during the rainy season between May and September.

On May 25, a funnel cloud was spotted west of Hong Kong International Airport.

Waterspouts were seen near Kau Yi Chau, an uninhabited island west of Victoria Harbour, and off Clear Water Bay in July and October 2015 respectively.

In June last year and August 2016, funnel clouds were reported in Sai Kung.