These bizarre images show a gigantic cloud of dust billowing over an African city.

The dust storm - known as a "Haboob" - gathered over Khartoum, the capital of Sudan in north east Africa yesterday.


They are caused by downdrafts created when a thunderstorm reaches its final phase. These downdrafts cause descending air to hit the ground and pick up large amounts of dust.

The gathering dust clouds then travel forward at a speed of 30 mph, creating the frightening spectacle. The dust storms can reach a height of 3,000 feet and contain a wall of sand up to 60 miles wide.

The word Haboob comes from the Arabic for "phenomena".

The Haboob also occurs in America, especially in hot dry states such as Arizona and Texas.