The haboob is a strong sand-/dustorm that occurs along the southern edges of the Sahara, the Sudan. The name comes from the Arabic habb, meaning 'wind' or 'to blow'. The haboob is often associated with thunderstorms and even small tornadoes. A haboob usually lasts about three hours and are strongest in April and May, but occur in every month except November. The wind direction may be north (in winter) or east, southeast or south (in summer). However, typically, the storm is experienced late in the day during summer, followed by some rain. The city of Khartoum, Sudan experiences an average number of about 24 hoboobs every year.
A haboob storm-front may transport and deposit large quantities of sand or dust material, which move as an extremely dense wall that can reach a height of 1000 metres (about 3,000 feet). Like its cousins the Sirocco (Mediterranean), the Khamsin (Egypt), and the Harmattan (West Africa) the Haboob derives from the the vast Sahara anticyclone interacting with moist air-masses from either the Gulf of Guinea or in winter from the Mediterranean.
In North America, sand- and duststorm walls associated with severe thunderstorms are also called haboobs. They are often caused by the gust-front of cold air from a supercell thunderstorm (downdraft). They are especially frequent in Arizona and Texas with wind speeds around 30 to 50 mph.