How does Sahara Dust Storms Impede the Destructive Nature of Hurricanes

  Before the start of each Hurricane Season (June 1 – November 30  5), meteorological forecasters predict the number and intensity of hurricanes (Hurricanes classified from a category one to a five. Most destructive hurricane sustained winds greater than 155 miles per hour. 9), based upon climate phenomenon La Nina or El Nino. Both of these phenomenons influence wind shear: Breaks up hurricanes by preventing them from rising in the air or less shear means atmospheric conditions could cause hurricanes to climb and intensify.  In the tropical Pacific Ocean unusual cooling of the sea surface referred to as La Nina: Wind shear reduced over the Atlantic Ocean (intensifies over the Pacific) tend to increase number of hurricanes. The center of National Ocean and Atmospheric Administration notes: “more hurricanes form in the deep tropics from African easterly waves. These Systems have a much greater likelihood of becoming major hurricanes, and of eventually threatening the U.S. and Caribbean Islands.” 1 “An El Nino occurs periodically when ocean temperatures rise in the eastern Pacific Ocean.” This atmospheric condition is conducive to cause upper level wind shear, suppressing hurricane formations, moving across the Atlantic Ocean. 2 Major influencing factor dampening hurricanes and offsetting predictions for El Nino or La Nina: Meteorological researchers studying westward movement of Sahara dust storms, crossing the Atlantic Ocean. 3 

   In the issue of Geophysical Research Letters published October 2006, researchers led by Amato T. Evan of the University of Wisconsin-Madison, discovered Sahara dust storms negatively influence tropical storm formations in the Atlantic Ocean.  4 In the Sahara desert, dust storms originate in West Africa (Hot desert air from the Sahara, collides with cooler dryer air from the south to form winds that loft sand and dust into the atmosphere.   3) May, June, July and early August.   6 Trade Winds pick-up the dust storm and whirl westward across the Atlantic Ocean (five days or more).   3 According to researchers a Sahara Dust storm crossing the Atlantic, could be sizable to the continental United States and cool the atmospheric temperature from one to two degrees Fahrenheit, during the summer. “Such a small difference can make a large difference in the number and intensity of hurricanes that form.”   Researchers theorizes the Sahara hot dry clouds of dust shear hurricanes or rip them apart, impeding the wind speeds at different altitudes. Also, Sahara dust storms infuse dry – air into storms, adversely defusing their intensity, otherwise moisture fuels a storm’s destruction nature. 7

  Researchers studied African dust storms (1982-2005), compared to tropical storm movement.  4  Researcher Amato Evan said: “In 2004, we saw an increase in dust activity and a decrease in hurricanes. In 2005, it was the exact opposite”: Most active hurricane season, including the most devastating hurricane Katrina (Estimated total property damage $81 billion and more than 1,836 people lost their lives  8) In early 2006, Amato Evan reasoned dust storm activity influenced a decrease in hurricane activity that year, contrary to meteorological forecasters predicting an active hurricane season. 3 

 Weather satellites track dust storms. On the ground dust storms shroud the appearance of sunsets, without visual impairment of the sun.  4  “Evan said he can predict African dust storms activity about eight months in advance.”  Starting in May 2008, before the beginning of hurricane season, The University of Wisconsin plans to forecast severity of hurricanes 7 Findings based upon patterns of precipitation in Africa during the previous year and quarter century of data.  Amato Evan said: “We have a computer model that takes the dust forecast and tries to estimate how much that dust storm activity will cool the ocean.” During years of low dust activity expected to correlate higher ocean temperatures, meteorologically conducive for intense hurricane activity. 10

  In 2008, U.S. National Oceanic and Atmospheric Administration, lead seasonal hurricane forecaster Gerry Bell confirmed dust is not a key element in current atmospheric forecasts. “However, he says that his colleagues at NOAA’s base in Miami, who predict hurricane tracks five days ahead throughout the season, do consider atmosphere’s dust load.” 11  Researchers at the Cooperative Institute for Meteorological Satellite Studies (staff of over 100 associates 13) suggest using dust storm activity, when forecasting upcoming hurricane season. 12

 William Lau, Chief of the Laboratory for Atmospheres at NASA’s Goddard Space Flight Center in Maryland said regarding the study of Sahara dust storms impede hurricane destruction: “We know El Nino is No. 1. Maybe African dust could become a close No. 2.” 6


1.) La Nina developing, could mean more hurricanes –

 2.) Climate change may weaken El Nino’s hurricane buffering effect –

 3.) African Dust Storms Stifle Hurricanes, Study Suggests –

 4.) Africa dust may hamper hurricanes –

 5.) 2010 Atlantic hurricane season –

 6.) Scientists examine African dust link to hurricanes –

 7.) African dust forecast could be new hurricane tool –

 8.) Hurricane Katrina –

 9.) Saffir-Simpson Hurricane Scale –

 10.) African dust storms forecast may help predict hurricanes –

 11.) Tracking desert dust could help hurricane prediction –

 12.) African Dust Forecast May Help Hurricane Season Predictions –

 13.) About CIMSS –