Haboob

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A haboob moves across the Llano Estacado toward Yellow House Canyon, near the residential community of Ransom Canyon, Texas (18 June 2009)

A haboob (Arabic: هَبوبhabūb "blasting/drafting") is a type of intense dust storm carried on an atmospheric gravity current. Haboobs occur regularly in arid regions throughout the world.

They have been observed in the Sahara desert (typically Sudan, where they were named and described), as well as across the Arabian Peninsula, throughout Kuwait, and in the most arid regions of Iraq.[1] African haboobs result from the northward summer shift of the inter-tropical front into North Africa, bringing moisture from the Gulf of Guinea. Haboob winds in the Arabian Peninsula, Iraq, Kuwait, and North America are frequently created by the collapse of a thunderstorm, while haboobs in Australia may be frequently associated with cold fronts. The deserts of Central Australia, especially near Alice Springs, are particularly prone to haboobs, with sand and debris reaching several kilometers into the sky and leaving up to 30 centimetres (1 ft) of sand in the haboob's path.

The arid and semiarid regions of North America—in fact, any dry region—may experience haboobs. In North America the most common terms for these events is either dust storm or sandstorm. In the U.S., they frequently occur in the deserts of Arizona, including around the cities of Yuma and Phoenix[2][3]—and in New Mexico and Texas.[4] During thunderstorm formation, winds move in a direction opposite to the storm's travel, and they 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.[5][6][7]

When this downdraft of cold air, or downburst, reaches the ground, it blows dry, loose silt and clay (collectively, dust) up from the desert, creating a wall of sediment that precedes the storm cloud. This wall of dust can be up to 100 km (62 mi) wide and several kilometers in elevation. At their strongest, haboob winds often travel at 35–100 km/h (22–62 mph), and they may approach with little or no warning. Often rain does not appear at ground level as it evaporates in the hot, dry air (a phenomenon known as virga). The evaporation cools the rushing air even further and accelerates it. Occasionally, when the rain does persist, it can contain a considerable quantity of dust. Severe cases are called mud storms. Eye and respiratory system protection are advisable for anyone who must be outside during a haboob. Moving to shelter is highly desirable during a strong event.

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References[edit]

  1. ^ Sutton, L. J. (1925). "Haboobs". Quarterly Journal of the Royal Meteorological Society 51 (213): 25–30. doi:10.1002/qj.49705121305. 
  2. ^ Idso, S. B.; Ingram, R. S.; Pritchard, J. M. (1972). "An American Haboob". Bulletin of the American Meteorological Society 53 (10): 930–935. doi:10.1175/1520-0477(1972)053<0930:AAH>2.0.CO;2. 
  3. ^ Idso, Carolyn W. (1973). "Haboobs in Arizona". Weather 28 (4): 154–155. doi:10.1002/j.1477-8696.1973.tb02253.x. 
  4. ^ Chen, W.; Fryrear, D. W. (2002). "Sedimentary characteristics of a haboob dust storm". Atmospheric Research 61 (1): 75–85. doi:10.1016/S0169-8095(01)00092-8. 
  5. ^ Farquharson, J. S. (1937). "Haboobs and instability in the sudan". Quarterly Journal of the Royal Meteorological Society 63 (271): 393–414. doi:10.1002/qj.49706327111. 
  6. ^ Lawson, T. J. (1971). "Haboob Structure at Khartoum". Weather 26 (3): 105–112. doi:10.1002/j.1477-8696.1971.tb07402.x. 
  7. ^ Membery, D. A. (1985). "A Gravity-Wave Haboob?". Weather 40 (7): 214–221. doi:10.1002/j.1477-8696.1985.tb06877.x. 

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