Sahara Desert Turns Green After Unusual Rainfall

The Sahara Desert, traditionally known for its dry, sandy expanses, is undergoing a surprising transformation. Recent satellite images from NASA show that heavy rainfall has resulted in green patches appearing across the desert, an extremely rare event for the region.

Unprecedented rainfall in the Sahara

This September, certain areas in the Sahara have received rainfall levels that are five times higher than the usual monthly average. 

North Africa, which includes parts of the Sahara, has been experiencing unusually high levels of precipitation, causing flooding in some locations. 

While rainfall isn’t completely uncommon in this region, the amount is typically very low, usually just a few inches annually, as reported by the NASA Earth Observatory.

Impact of an extratropical cyclone

On 7 and 8 September, the region was hit by an extratropical cyclone. This type of storm doesn’t meet the criteria for a tropical cyclone but can still bring significant rainfall. This particular storm dumped a large amount of water, leading to substantial runoff across the desert.

NASA’s satellite images reveal the changes

NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) captured images of this event. 

MODIS, which is carried aboard two satellites, is capable of photographing Earth’s surface every one to two days. 

By comparing before and after images, NASA detected more water in the region and new patches of green vegetation. 

In the photos, the depth of water appeared in different shades of blue, while the greenery indicated that life was returning to some areas of the desert.

One particularly noteworthy image showed a typically dry lake in the Sahara, which has now been filled with water. 

This type of event is incredibly rare in this part of the world, but the heavy storms have made it possible.

Why is the Sahara receiving so much rain?

There are a couple of scientific theories explaining why this is happening. One explanation focuses on the Intertropical Convergence Zone (ITCZ), a belt of storms near the equator where air from both hemispheres meets. This zone moved northward toward the Sahara, causing storms to occur over the desert.

Another theory suggests that the waters in the North Atlantic Ocean and the Mediterranean Sea have warmed more than usual, which may be contributing to the increased rainfall in North Africa. Some experts believe these conditions could continue, possibly bringing even more rain to the region in the future.

Historical rainfall events in the Sahara

Although this much rainfall in the Sahara is rare, NASA reports that heavy rainfall events have been recorded before. 

More than 38,000 extreme rainfall incidents have been documented since weather records began. A significant portion of these rains occurred in the summer and were often linked to extratropical storms like the one seen recently.