Two trapped in flooded underpass die

Small-scale convective weather that can hit areas within a few kilometers is hard to forecast, a meteorologist said on Tuesday, after two people died in Beijing when a car under an overpass was hit by a flash flood.

Eighty millimeters of rain fell in the city's Haidian district in around an hour from 9 pm on Monday. The water accumulated at a low-lying road under an overpass in the district, trapping a passing car.

Watermarks on the side of an arch showed the water on the road had reached a depth of about 2 meters, Beijing News reported.

The Haidian district meteorological service issued a blue alert for heavy rain and 25 minutes later raised the alert level to orange, the second-highest in a four-tier warning system.

The Beijing Drainage Group and firefighters rescued the two people from the car, but they died in hospital on Tuesday morning.

A video showed that water elsewhere in western Beijing reached a pedestrian's knees. In the Shijingshan district in the west, a tree uprooted by the rain smashed into a car.

Around 6 am on Tuesday, the service took down the rain warning.

Meteorologist Zhang Mingying told Beijing News that the short but heavy rain that hit the district was called a "supercell rainstorm", which forms from part of a strong cloud and can usually bring disastrous weather.

"This kind of rain forms and disappears very quickly, sometimes persisting only two or three hours, so current technology can forecast it only hours ahead," he said. "It is hard to predict it a day or even two days in advance like normal weather reports do."

Zhang said that alerts from Haidian's meteorological service showed it reacted to the rain in a timely way.