July 30, 2012 – ARIZONA - A second cloud of yellow in less than a week overwhelmed suburban Phoenix on Sunday, mixing with torrential rains and gusty winds that wreaked havoc on midday traffic in the area. The thick wall of dust, known as a haboob, which is Arabic for ‘strong wind,’ was seen making its way through the town of Laveen about eight miles southwest of downtown Phoenix. The greater Phoenix area and northwest and north central Pinal County were under a dust storm warning that expired at 7pm on Sunday. This comes just days after an enormous dust cloud measuring around 2,000 feet tall and almost 100km wide swept over the city, traveling at 35mph. The dust cut power to some 9,000 homes and caused disruptions at the local airport. Caused by Arizona's monsoon season which begins in early June and runs through till the end of September, haboob's only occur in Africa, the Middle East, Australia and Phoenix, Arizona. Known as the grand daddy of dust storms, the haboob is a rare event and is caused by loose dust being blown upwards in the absence of rain and collecting skywards where it is then propelled by another more distant thunderstorm brewing behind it. Despite some of the 1.5 million residents of Phoenix objecting to the term haboob being used, meteorologists in the city confirmed that they have been using the Arabic word to describe the massive dust storms for over 30 years. 'I think what's going on is that we've had a higher frequency of stronger dust storms over the last couple of years and the term has been in play much more because of that,' said Ken Waters of the Phoenix National Weather Service office to KPHO. Blowing gusts of up to 50 mph at Phoenix Sky Harbor Airport, the haboob is destructive because of the fine dust particles that manage to permeate everywhere during the storm. –Daily Mail