ABOUT THE SAHARAN AIR LAYER

A river of dust that crosses an ocean.

Each year, the Sahara exports more than 180 million tonnes of dust. Tens of millions of tonnes complete the full Atlantic crossing — reshaping skies, soils, and storms on three continents. Here’s the science behind what we track.

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What is Saharan dust?

The Saharan Air Layer (SAL) is a mass of very dry, dusty air that forms over the Sahara Desert in late spring, summer and early fall. As it moves off the West African coast, it can extend from roughly 1 to 4 miles up in the atmosphere.

Trade winds push this layer westward across the tropical Atlantic in pulses every few days. A typical plume reaches the Caribbean in 5 to 7 days and can continue on to Florida, the Gulf Coast and Texas.

BY THE NUMBERS

Dust lifted from the Sahara each year

~180 Mt

Reaching the Amazon & Americas

~28 Mt

Typical crossing time to Caribbean

5–7 days

Peak season

Jun–Aug

The crossing, step by step

Follow a single pulse of dust from the desert floor to a Caribbean sunset.

WEST AFRICA · DAY 0

Lift-off

Dry convection and gusty winds over the desert loft fine mineral dust thousands of feet into a hot, dry air mass.

OPEN ATLANTIC · DAY 1–4

Transport

Easterly trade winds and a mid-level jet carry the layer westward at 20–30 mph, holding the dust aloft.

LESSER ANTILLES · DAY 5–6

Arrival

The plume reaches the eastern Caribbean — milky-white skies, hazy sun and rising particulate levels.

CARIBBEAN → US · DAY 6–8

Spread

Remnants drift over Cuba, Florida and the Gulf, fading into vivid sunsets and a faint desert haze.

The good & the bad

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WHY IT MATTERS

Fertilises the Amazon

Phosphorus-rich dust replenishes nutrients washed out of rainforest soils by heavy rain.

Suppresses hurricanes

Dry, stable, sheared air robs tropical storms of the moisture and lift they need to organise.

Builds Caribbean beaches

Over millennia, settled dust has contributed iron and minerals to island soils and sands.

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THE RISKS

Degrades air quality

Fine PM10/PM2.5 particles raise AQI and can trigger respiratory and cardiac symptoms.

Hard on sensitive groups

Children, the elderly, and people with asthma or COPD feel the effects first and most strongly.

Reduces visibility

Dense plumes mute the sun, cut visibility and leave a fine film on surfaces.

THE HURRICANE CONNECTION

Dust that calms the tropics

The Saharan Air Layer carries three ingredients that suppress tropical storms: extremely dry air that starves developing systems of moisture, strong vertical wind shear from the embedded mid-level jet, and warm, stable air aloft that caps the thunderstorms a hurricane needs to grow.

When the SAL is active over the Atlantic, the hurricane season often goes quiet — which is why forecasters watch the dust as closely as the storms.

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How we track it

We blend satellite imagery, aerosol reanalysis and dispersion models into a single readable forecast. Our data comes from public scientific sources:

NASA MERRA-2

Aerosol optical depth reanalysis used for concentration estimates.

NOAA GOES-East

Geostationary satellite imagery of the dust band in near real time.

Copernicus CAMS

European atmospheric composition and dust forecast model.

EUMETSAT

Meteosat imagery tracking dust as it leaves the African coast.

About this data. saharandust.com is an independent educational project. We combine public scientific sources — NASA, NOAA, EUMETSAT and Copernicus — into a single readable view of the Saharan Air Layer as it crosses the Atlantic. For health and safety decisions, always consult your national meteorological and health authorities.

See the plume in motion

Scrub through a 7-day forecast on the live map.