HOUSTON – At KPRC 2, we’re dedicated to keeping Houstonians informed. As part of our Ask 2 series, the newsroom will answer your questions about all things Houston.
The question: Is there a correlation between Saharan dust storms and tropical activity in the Atlantic Ocean?
The answer: Saharan dust, also known as the Saharan Air Layer (SAL), inhibits tropical activity in the Atlantic Ocean. The SAL is warm, dry, dusty air coming off the Saharan Desert in Africa. During the summer months, in particular, waves of these dust plumes move off the western coast of Africa, get caught up in the prevailing easterly wind, and migrate all the way to North America.
When these dust plumes are present, hurricanes are usually not. There are several reasons why:
The SAL is a very dry air mass. Hurricanes need deep tropical moisture to form.
The SAL is a warm air mass. It comes off the coast of Africa warm and stays that way. The dust absorbs some sunlight, reflects some sunlight back into outer space, and only allows a portion of the sun’s rays to penetrate all the way to the ocean surface. In effect, the SAL robs the ocean surface of warm sunshine, keeping the surface air and water cool and the dust layer warm.