>> look at the size of this thing. oh, yeah. >> you can't escape it. hot, dry weather is the stuff of legend in the sprawling metropolis of phoenix, arizona. here in the valley of the sun, summer temperatures can exceed 100 degrees for weeks on end. being surrounded by desert only makes things hotter. on july 5th, 2011, the combination results in a spectacular phenomenon that fills the sky. >> the storm spanned from one side of the horizon to the other. >> this time lapse must be seen to be believed. the storm is called a haboob. >> an arabic term and it means wind. we generally just use the word dust storm. >> the wind from a dying summer thunderstorm kicks up enough dust to produce a dense, massive wall, advancing towards the city.