Sandstorms can travel thousands of kilometers because strong winds carry them over long distances. Sand particles are lifted into the atmosphere and transported by atmospheric currents over vast areas.
The formation of a sandstorm often begins with prolonged periods of drought and intense heat. The soil, completely dried out, loses its protective vegetative layer, making it particularly vulnerable to the slightest gust of wind. If strong winds suddenly blow—often associated with an atmospheric disturbance or a dry thunderstorm—they then massively lift dust and sand into the air. The warm air at the ground rises quickly, further amplifying the force with which the grains are propelled into the sky. Once in motion, this phenomenon can rapidly escalate into a huge storm.
Sandstorms consist of a multitude of fine particles, which remain suspended for a long time due to their small size, sometimes less than a few micrometers. The lighter these particles are, the more easily they are lifted by air currents. Their shape also plays a role: those that are irregular or flattened offer more resistance to air, helping them to stay suspended. Once propelled into the air, these tiny grains take advantage of atmospheric turbulence that makes them swirl without quickly falling back to the ground. Basically, as long as the wind remains strong and the atmospheric currents carry them, these dust particles can float for several days.
Sandstorms often take advantage of true aerial highways: atmospheric currents. Up there, these large air corridors — particularly the jet streams — race across thousands of kilometers, carrying dust and sand over surprising distances. When a storm reaches these powerful winds at altitude, the particles remain suspended for days and easily cross borders, even continents. It's a bit like the sand hitchhiking on a fast highway, traveling far without tiring. These currents directly influence the distance traveled and the direction taken by the storms, sometimes allowing them to cross entire oceans.
Relief can deflect, slow down, or even stop a sandstorm. When a mass of air laden with sand encounters a mountain range, it must either rise in altitude or change direction. If it rises, the air cools, becomes denser, and drops some of the sand it carries to the ground. Oceans often act as natural barriers: when a sandstorm reaches over the sea, humidity and cooler marine air can accelerate the fall of sandy particles. However, it also happens that the sand completely crosses the ocean, carried by powerful atmospheric currents, sometimes reaching other continents thousands of kilometers away.
The sandstorm of the Sahara in June 2020 is a good example: a huge dust cloud crossed the Atlantic Ocean, reaching the Caribbean, and then touching the American coasts over 8,000 kilometers away from its starting point. Similarly, every year dust from the Gobi Desert in Central Asia travels thousands of kilometers to cover regions as far away as Japan and even the west coast of the United States. The regularity of these long-distance journeys clearly shows that these storms can span entire continents, carried by powerful winds at high altitudes.
Sandstorms can influence air quality far from their region of origin. In Europe, for example, some cities occasionally experience spikes in pollution caused by Saharan particles that have traveled thousands of kilometers.
Some resistant bacteria can remain alive and travel thousands of kilometers, carried by sand particles from storms. This can influence the ecology in remote areas and also creates a particular interest in studying large-scale microbiological exchanges!
Every year, sandstorms from the Sahara carry about 180 million tons of dust to the Amazon! These mineral particles play a crucial role by providing vital nutrients to the rainforest.
The very fine particles in sandstorms can reach altitudes of several kilometers and remain suspended for several days or even weeks, thus allowing them to easily cross oceans.
During a sandstorm, it is advisable to stay indoors, close windows and doors, wear a respiratory mask if necessary, and humidify the indoor air if possible to minimize the inhalation of fine particles.
Yes, climate change influences the frequency and intensity of sandstorms. Certain phenomena such as prolonged drought, increased desertification, and changes in weather patterns can enhance the frequency, duration, and geographical reach of these storms.
Satellites equipped with specialized sensors enable the real-time detection and tracking of the movements of sand and dust particles in the atmosphere. These tools provide valuable information on the trajectory, altitude, and temporal evolution of storms.
Although often detrimental, sandstorms can also carry essential nutrients over long distances, thereby fertilizing certain remote ecosystems, such as the Amazon rainforest, which benefits from minerals brought from the Sahara.
Sandstorms can cause respiratory issues, irritate the eyes, and exacerbate existing health problems such as asthma or allergies. The dust carried by these storms sometimes contains fine particles or pollutants that can have effects on cardiovascular health.
No one has answered this quiz yet, be the first!' :-)
Question 1/5
