Haboobs are recurring dust storms in Sudan. (In America, we have our own haboobs, known as "Arizona dusters".) The word haboob means "violent wind" in English. Haboob itself is Arabic.
Haboobs strike most often in the months between May and September. They can come from any direction, regardless of the wind at the time. There can be up to thirty (30) such storms a year.
The dust cloud alone can be as high as 10,000 (ten thousand) feet tall, and 100 (one hundred) miles miles wide. The visibility (sight length) can be from a quarter mile to zero. The dust in the air could stay there for days.