Saharan dust plumes aren’t unusual. They’re very common. According to the Hurricane Research Division, they happen every 3 to 5 days from late Spring to Early Fall.
They’re referred to as the Saharan Air Layer because they originate from the Sahara Desert.
But what is unusual about this particular plume is the thickness. It has the highest concentration of dust particles in over 50 years. This is why it’s so easily picked up by the satellite. Our satellite imagery has improved greatly over the years and the views from above are amazing!
So here’s what it’s not. It’s not like the dust storms we see sometimes in the southwestern United States or in the Middle East. Those are closer to the ground and impact life a lot more.
Here’s what it is – it’s a thick layer of dust that’s moving with the easterly wind over the Atlantic from West Africa – which is the Earth’s largest dust source. The dust is suspended in the sky anywhere from around 5 thousand feet to 20 thousand feet. Most jetliners can fly higher than the dust plume.
It’s made a nearly five thousand-mile journey across the Atlantic and the thickest of the plume has already moved through the Caribbean. It arrives in the United States as early as today (6/24/20) and the upper atmospheric circulation will have it hanging out over the SE through the weekend. It won’t make its way to North Dakota at all. It’ll get picked back up by the westerlies and carried back out to sea.
In its journey, some dust will settle leaving a thin layer in some areas. The sky can also turn a little dark, if not kinda milky-looking. It may impact temperatures a bit much like wildfire smoke can do for us here.
It’ll also make for picturesque sunrises and sunsets. That’s because the light will refract through all of the dust particles in the atmosphere making for more beautiful colors than normal.
It’s still not clear whether it’ll reduce air quality in the southeastern United States but it’s being monitored.
Something this Saharan dust plume will also do is suppress tropical activity. This dust helps keep a lid on some cloud formation which means it can weaken tropical cyclones or suppress their growth. So the tropics have been quiet this week.
Scientists also believe the nutrients transported in the plume from the Sahara Desert have in fact helped build and nourish the coral reefs in Florida, the Bahamas, and the Caribbean.