by Curlan Campbell, NOW Grenada
- Another plume of Saharan Dust is heading towards the Caribbean
- Drier atmospheric conditions can help suppress hurricane formation
Forecasters warn that off the coast of Africa another plume of Saharan Dust is heading towards the Caribbean. The region is already engulfed with the first wave of the microscopic dust particles which are common around this time of year.
This atmospheric phenomenon is transported across the Atlantic Ocean by northeast trade winds and is characterised by unusually orange hue skies.
Wayne Williams, a meteorologist at the St George’s University (SGU) says the Saharan Dust normally coincides with the hurricane season and brings with it drier atmospheric conditions which can help to suppress hurricane formation.
“Studies have shown that because of the dry air, it tends to help suppress hurricane formation or hurricane strengthening and, on the flip side enhances rain production because it will produce what we call condensation nuclei. A few years ago we had tropical storm Maria which was engulfed in a body of Saharan Dust and the theory is that it helped to weaken it; but it doesn’t mean that it eliminates hurricanes.”
Williams said varying factors makes it difficult to predict the length of time this atmospheric condition will persist. “There is no set time because it depends upon the intensity of the storm that produces it over the Saharan Desert and it depends on how much dust is actually there. Also, it depends on how thick the layer is in the atmosphere and the strength of winds bringing it over. Stronger winds will tend to dissipate it faster.”
Meanwhile, the health implication for the arrival of the Saharan Dust spells trouble for people coping with respiratory illnesses says Public Health Specialist, Dr Francis Martin.
Dr Martin has conducted and published a study on the health risk associated with the Saharan Dust entitled “Saharan dust, climate variability, and asthma in Grenada, the Caribbean.” A summary of the study indicates that all asthma visits to the emergency room over 5 years (2001-2005) were compared to the dust cover and climatic variables for the corresponding period. Variation in asthma was associated with change in dust concentration; asthma was positively correlated with rainfall and rainfall was correlated with dust.
Dr Martin said there is a direct correlation between a spike in asthmatic conditions and the arrival of the Saharan Dust particle concentration in the atmosphere. “From a public health standpoint, public health professionals need to be able to be up on their treatment protocol and guidelines because we expect more asthmatic conditions to come in: parents and children who are at risk of asthma and also skin conditions. Interestingly then you know at those times you need to pay more attention to your child’s nutrition… so that you know that the child eats the type of foods that encourage healthy immune response. And for the people with skin conditions [they should be] wearing long sleeves to protect the skin.”
The Saharan Dust can also place healthy people undiagnosed of asthma at risk of suddenly developing the condition and will put people suffering from cystic fibrosis more at risk.
Williams predicts that the second wave of dust will be over the region by the middle of this week.