(Photo by Chris Cheng)
So far, 2020 has been a year to remember, and you can add another rare event to the year's time line: a Saharan dust cloud making its way to northern Illinois. The upshot of this unusual occurrence is that we may experience some picture-perfect sunrises and sunsets.
Dust from the Sahara Desert in Africa traveling across the Atlantic Ocean is a normal occurrence, but an event of this magnitude is noteworthy because of its intensity and magnitude, the Washington Post reports.
These air masses, called the Saharan Air Layer, or SAL, consist of dust held aloft in warm, dry air. They typically form over the Sahara Desert from late spring to early fall each year. Every three to five days, dust from the SAL moves out over the Atlantic Ocean, according to the National Oceanic and Atmospheric Administration. The peak period for SAL activity is mid-June to mid-August, and during that peak period the dust associated with it is more likely to travel further west and cover a greater area.
That's exactly the situation we find ourselves in right now. A dust plume from the Sahara has already traveled more than 4,000 miles across the Atlantic and into the Gulf of Mexico, The Weather Channel reports. It is forecast to reach the southeastern United States by the end of the week and up into the Ohio Valley and points north, even stretching up to northern Illinois, by the end of the weekend.
The dust plumes typically become less concentrated, with fewer dust particles, the further west they travel, and the forecast models for this plume show northern Illinois at the outer limit of how far it will extend north and west. In our area, the skies may appear a little more hazy than usual as a result of the dust plume, and we may experience some spectacular sunrises and sunsets.
This effect on sunrises and sunsets is because of how the particles in the air interact with the sunlight and cause the light to be scattered. With more dust in the atmosphere, more light is refracted, causing us to see more reds, oranges and yellows at sunrise and sunset, USA Today reports. We occasionally experience a similar phenomenon in northern Illinois when smoke from Canadian wildfires drifts south along upper-level winds, causing hazy skies and sometimes picture-perfect sunsets.
Hundreds of millions of tons of dust from the deserts of Africa are blown across the Atlantic ocean each year, fertilizing soils in the Amazon and building up beaches in the Caribbean, according to NASA. The SAL also suppresses the formation of tropical storm systems in the Atlantic, so it is of great interest to hurricane forecasters.
The SAL can have negative effects as well, reducing air quality even in places far from the Sahara, The Weather Channel reports. The extra particulate matter in the atmosphere can cause layers of dust to develop on surfaces and can cause breathing difficulties for people with respiratory conditions such as asthma. People at risk of experiencing negative effects should monitor air quality reports for their area.
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