Q&A – What’s El Nino’s Impact on Saharan Dust During Hurricane Season?
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Today’s entry: Morning, Brian. I appreciate you playing my talk back, but the most important part of the question was, will El Nino affect the Saharan dust plumes? Or could we possibly have a 12 punch in minimizing our chances for hurricanes this season? Thank you. God bless.
Bottom Line: Today’s question picks up on two hugely important themes of hurricane season – including the most understated, but potentially most important one. The impact of Saharan dust.
As I’ve covered extensively in recent years, Saharan dust is a pest for people with respiratory conditions like my wife Ashley, but it’s our best friend when we’re in hurricane season. That’s due to the findings of recent studies showing Saharan dust has become the single biggest factor in whether tropical formation takes place and how much rain is concentrated in storms that do form.
As my subsequent research has shown, typically, Saharan dust plumes crossing the mid-Atlantic end in late July or early August leading to what are typically the four most active weeks of hurricane season – the last two weeks of August and first two weeks of September. As we’ve seen in recent years, our greatest hurricane threats haven’t come from the Atlantic but rather from the Gulf.
There are many factors that have played into why that’s been the case, but one of them was the lack of Saharan dust. Commonly the Saharan dust that had made its way across the Atlantic, it didn’t continue into the Gulf. That was different last year. Most of the plumes (an average of two per week), made their way not only across the Atlantic, into the Caribbean, but also into the Gulf of America.
What we’ve seen is that with higher global temperatures, we’ve had more Saharan dust, that’s been increasingly lasting longer into the hurricane season. So enter into this conversation the considerations posed by El Nino. Here’s what we know based on history...
Typically, what we see is... More dust during El Niño: Studies show that some of the dustiest years recorded in the Atlantic coincide with El Niño events. El Niño often leads to drier conditions in parts of Africa, which reduces vegetation cover and increases dust activity. And when the two of them combine, what we see is the potential for increased hurricane suppression.
Dust plumes bring dry, stable air and often increase wind shear, which inhibits tropical cyclone formation and intensification. El Niño already suppresses Atlantic hurricanes via increased wind shear, so extra dust can amplify this effect. As you might expect, if each of them can serve as a hurricane repellant on their own, the combined effect can produce even stronger results. This is all part of the potentially good news with both of them.