A rare and intense deluge is currently sweeping across the Sahara, one of the driest regions on Earth. While the exact reasons for this unusual rainfall remain unclear, some scientists believe it may be linked to a quieter-than-usual Atlantic hurricane season.

The downpour has been so significant that typically arid areas of North Africa are experiencing monsoons and flooding, with parts of the Sahara forecasted to receive up to five times their average rainfall for September.

Although precipitation in the Sahara isn’t unheard of—given the region’s vast size and diversity—this event is notable because it has affected areas farther north, which are usually much drier, according to Moshe Armon, an atmospheric scientist at ETH Zürich. Armon adds that larger portions of the desert are being soaked compared to typical rainfall patterns.

Some experts believe this could be part of Earth’s natural climate variability, while others attribute it to human-driven climate change. "The truth likely lies somewhere in between," Armon noted.

One possible factor behind the increased rainfall is the unusually quiet Atlantic hurricane season. This year, despite predictions of intense activity fueled by warm ocean temperatures, the season has been calm, with no named storms forming over Labor Day weekend—the first time this has happened in 27 years.

Jason Dunion, a meteorologist with NOAA, explains that "more than half of named storms and 80% to 85% of major hurricanes in the Atlantic each year typically form from atmospheric waves south of the Sahara." Normally, these waves travel west across the Atlantic along the Intertropical Convergence Zone (ITCZ), a belt near the equator where the Northern and Southern hemispheres’ trade winds meet. When conditions are right, these waves combine with warm Atlantic waters to form tropical storms and hurricanes.

Satellite imagery of the Sahara before (August 22nd, 2024, left) and after (September 10th, 2024, right) the rains.

This year, however, the ITCZ appears to have shifted farther north, over the Sahara itself. While the exact cause remains uncertain, some climate models have predicted that warming oceans and atmospheric temperatures—driven by greenhouse gas emissions—would eventually push the ITCZ northward. The Northern Hemisphere has been heating more rapidly than the Southern Hemisphere, contributing to this shift.

As a result, rainfall is being carried farther north into the Sahara, while the atmospheric waves needed to generate hurricanes are displaced from their usual paths. With less moisture from the ITCZ feeding into the Atlantic, the conditions for severe storms are less favorable. That said, the peak of the hurricane season typically falls in mid-September, so a lull doesn't rule out the possibility of dangerous storms later on.

Meanwhile, the increased rainfall in the Sahara could also be attributed to the unusually warm waters in the North Atlantic and Mediterranean Sea. When storms interact with these warmer waters, the chances of heavy precipitation rise significantly.

Looking ahead, the Sahara may experience more frequent wet conditions. As oceans absorb more heat due to human activities, some climate models suggest that monsoon rains will continue to shift further north in Africa by the year 2100.

This could mean increased rainfall in areas of the Sahara that are typically dry, with predictions indicating that ongoing greenhouse gas emissions could make the desert even wetter in the future.

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