PEMBROKE PARK, Fla. – It’s an amazing journey. A massive cloud of dust weighing as much as 200 million tons travels a vast distance across the Atlantic Ocean. The dust is lofted into the air from gusty winds over the Saharan Desert. It then rides the wind westward at elevations of one to four miles above the surface. And we will see it arrive in South Florida this week, the peak of which looks to be Thursday and Friday.
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We see dust migrations annually, generally from mid-June through early fall, but this particular dust plume is stronger than usual, which can have both positive and negative effects.
The dust can have positive environmental impacts. Such is the case with the Amazon rain forest, where fertilizing phosphorous replenishes depleted supplies. Phytoplankton in the ocean also benefits, as they absorb nutrients from the dust.
In South Florida, the most obvious impact is on the color of the sky. The typical rich blue hue is replaced with a hazy, milky appearance, not unlike what you may expect from smoke during a wildfire. Radiant and spectacular sunrises and sunsets occur, as the dust scatters the sunlight, leaving vibrant shades of red and purple as the dominant colors.
The dust can also be destructive. It can contribute to the bleaching of coral reefs in the Caribbean. Harmful fungi from the desert can hitch a ride within the dust cloud and then get deposited onto the ocean. These fungi seep into the reefs, attacking the reef and promoting the growth of harmful algae.
It also brings a risk of poor air quality as some of it settles to the ground and into our lungs. Those with breathing issues such as asthma, chronic obstructive pulmonary disease, and allergies must try to stay indoors as much as possible.
Expect a reduction in the rain late this week, as the dust dries out the atmosphere and stunts storm coverage. This is also the reason why large dust outbreaks tend to reduce tropical cyclone formation. But with less rain and more sunshine, temperatures will be searing hot. The heat index may topple 105 degrees in the peak heat of the day in some spots.