HOUSTON DUST
What's been called the most significant dust cloud in 50 years has now shrouded the U.S. Gulf Coast in a thick, dusty haze. The dust layer, which originated in the Sahara desert and drifted across the Atlantic, is forecast to continue moving north and east through the weekend, impacting areas from Texas and Florida all the way up to as far north as the Canadian border.

For most people, the dust will merely be a nuisance, but for many who have breathing issues the extra particulates in the atmosphere can cause complications. The timing couldn't be much worse, considering that a recent Harvard study shows that long-term exposure to fine particles of pollution in the air, much like dust, may be linked to higher rates of hospitalization and death due to COVID-19.



Currently the dust is thickest from Texas to Florida.


The dust is responsible for the dense haze shrouding Houston's skyline in the photo below.

Downtown Houston is cloaked in haze as a Saharan dust cloud moves over parts of Texas on Friday, June 26, 2020.
© DAVID J. PHILLIP/AP
Downtown Houston is cloaked in haze as a Saharan dust cloud moves over parts of Texas on Friday, June 26, 2020.
Most of the dust layer exists far above the surface — mostly between a few thousand feet above the surface to about 15,000 to 20,000 feet up. However, vertical mixing of the atmosphere and rainfall can bring that dust to the ground, and that's when it can become harmful to people with respiratory issues.

In some places, like the Southeast, enough dust will settle that odds are people there will be able to see a thin layer of dust on their cars.





The dust plume is forecast to break into two chunks due to a split in steering flow in the mid levels of the atmosphere, which will act as a guide.

One part of the dust cloud will be pulled northward from Texas through the Plains States and Midwest this weekend, and even to the Canadian border on Monday morning. The dust will diffuse and thin out dramatically by the time it reaches the nation's middle, but cities like Kansas City, Minneapolis and Chicago will see a hazier than normal sky. The dust in the atmosphere will also make for some especially vivid sunrises and sunsets.


Now, dust has both negative and positive impacts.

On the positive side, for millions of years dust has been transported by the east-to-west trade winds from Africa across the Caribbean to Florida, supplying much of the soil, and nutrients in the soil, for growth of vegetation. Scientists believe that the nutrient load in the environment around Florida and the Bahamas is otherwise so poor that without the African dust, the coral reefs would have had a hard time growing and flourishing. Dust plumes also supply much of the nutrients to sustain life in the Amazon rainforest.


(Read more here)