In contrast to the damaging dust storms that afflict southeast Asia, dust storms that originate in Africa's Sahara desert are thought to be important in sustaining life in some other parts of the world. About half of the Saharan dust comes from a small region called the Bod Depression where a gap between the Tibesti and Ennedi mountains forms a natural wind tunnel through which winds blow across the Bodele Depression picking up an average of 700,000 metric tons of dust in a