Waterspout seen over the seas west of Hong Kong: Observatory

A waterspout over the sea near Hong Kong was reported on Friday afternoon, according to the Observatory.

The weather forecaster announced the sighting at 4.53pm, where a rapidly rotating water column was spotted at sea to the west of the city. It added that a tropical disturbance from the South China Sea was bringing unsettled weather to the region.

“It is expected that the disturbance will move northwards and edge closer to the coast of eastern Guangdong gradually today and tomorrow, and will bring showers and thunderstorms to the region,” a spokesman said in the evening.

The Observatory said it would closely monitor the situation.

Witnesses said earlier on Friday that the waterspout, which spun out of dark clouds and the sea, lasted a few minutes.

A waterspout, called a water tornado in Chinese, is a rapidly rotating column containing water droplets, linking the base of a convective cloud and the water surface. Its wind speed is often slower than that of a tornado that occurs over land.

Leung Wing-mo, a former Observatory assistant director, said such a waterspout typically resulted from a combination of weather conditions.

“A convection current may simply cause a rainstorm. For a tornado or a waterspout to appear, a wind shear in the air needs to happen, where the wind direction and speed between the lower and upper layers of the atmosphere differ,” he said.

Leung said the waterspout reported on Friday occupied a small area in the sea, but warned it could cause some damage since wind speeds would be high at the centre of its rotating vortex.

“It’s a special situation, as I think in general the chance for a waterspout to appear today is low,” Leung added.

Hong Kong last reported a waterspout on April 22 in waters off Sai Kung’s Clear Water Bay.

The Observatory at the time also issued an amber rainstorm warning that lasted for nearly four hours, with the city wracked by violent gusts of wind and flooding occurring in some low-lying and poorly drained areas.