China sandstorm
© XinhuaA street in Dunhuang is shrouded in floating dust during the storm, April 23.
A dense sandstorm turned day into night in Jiuquan in northwestern China's Gansu province on Wednesday afternoon, with visibility dropping to as low as 50 meters. Local authorities have since issued the highest dust storm warning for the area, reports the state-run China News Service.

A local resident told the news agency that it was as dark as evening by 3pm, with fierce wind and dust battering the city. Another local internet user said it was pitch dark in Dunhuang, a county-level city in Jiuquan, by around 2pm on the same day. The sky turned reddish-orange around half an hour later, the internet user said.

Dunhuang's Mogao Caves, a UNESCO World Heritage Site otherwise known as the Caves of the Thousand Buddhas, was forced to close earlier than usual due to the storm. Visiting tourists were informed of the cause and related authorities arranged for their safe trips home.

A local meteorological station recorded visibility to be less than 50 meters in the desert city of Dunhuang and less than 500 meters in neighboring Subei Mongol autonomous county. Meanwhile, the strong winds reached level 10, or 89-102 kilometers per hour. The station predicted the storm will cover the entire Jiuquan area until Thursday afternoon.

The sandstorm is a natural phenomenon that takes place every year in the region, and often affects agricultural activities and may cause the temperature to drop by 10 C, China News Service said.