Thousands of homes are left without electricity after the dust storm hits, followed by lightning that struck two buildings

A massive dust storm has hit the US state of Arizona, leaving more than 4,500 homes without power.

The storm arrived in Maricopa County around 2pm on Friday local time, with high winds kicking up dust over the city of Phoenix.

Arizona's 3TV reported that the wins were so strong they bent goal posts on a football field in Tempe and a Special Olympics opening ceremony had to be cancelled.

Jerry Ferguson, who piloted the news company's helicopter during the storm, said what he saw was more dense than any other storm seen during the summer.

He said: "The storm is quite a large dust storm, both in height and breadth."

Thunderstorms were expected to follow the dust, with Phoenix's fire department saying lightning struck a two-storey apartment building, causing a small fire on the roof.

A second lightning strike hit a hotel across the road from the apartments, but there were no injuries reported from either strike.