Licensed from Columbia University Press
During thunderstorm formation, winds move in a direction opposite to the storm's travel, and they will move from all directions into the thunderstorm. When the storm collapses and begins to release precipitation, wind directions reverse, gusting outward from the storm and generally gusting the strongest in the direction of the storm's travel.When this downdraft, or "downburst", reaches the ground, dry, loose sand from the desert settings is essentially blown up, creating a wall of sediment preceding the storm cloud. This wall of sand can be up to 100 km (62 miles) wide and several kilometers in elevation. At their strongest, haboob winds can travel at 35-50 km/h (20-30 mph), and they may approach with little to no warning. Often rain is not seen at the ground level as it evaporates in the hot, dry air (a phenomenon known as virga), though on occasion when the rain does persist, the precipitation can contain a considerable quantity of dust (severe cases called "mud storms"). Eye and respiratory system protection are advisable for anyone who must be outside during a haboob -- moving to a place of shelter is highly desirable during a strong event.
Across North Africa and the Near East, there are many regional names for this unique sandstorm. The word haboob comes from the Arabic word هبوب "strong wind or 'phenomenon'."
See also
Notes
External links
- Haboobs, Arizona Department of Transportation.
- The Bibliography of Aeolian Research
- Yahoo Video of a Phoenix Haboob
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Last updated on Friday January 25, 2008 at 02:36:31 PST (GMT -0800)
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