A satellite image reveals an unusual “whirlwind” of clouds lurking off the coast of Spain and Portugal. Researchers are uncertain about what caused the rotation of this strange structure, but oceanic vortices and extreme heat waves may play a crucial role.
This striking image showcases an unusual spiral cloud perfectly nestled along the western coast of the Iberian Peninsula.
A large spiral cloud has been discovered perfectly nestled along the western coast of the Iberian Peninsula. Researchers are not exactly sure what created this unusual perfect shape. (Photo: NASA Earth Observatory/MODIS/)
The spiral consists of humid air and numerous clouds from the sea swirling together with dry air from the land, caused by a phenomenon known as a vortex—a mechanism similar to what is responsible for creating tropical storms such as hurricanes, cyclones, and tornadoes, according to the NASA Earth Observatory.
However, in this case, the rotation is much slower and weaker than that in tropical storms, preventing the dry air and clouds from mixing completely and hindering the formation of a proper vortex. This also prevents any clouds from drifting inland.
Stephen Joseph Munchak, a meteorologist at NASA’s Mesoscale Atmospheric Processes Laboratory, stated: “The exact cause of this [unusual] rotation at mid-latitudes remains a mystery. However, it may be driven by a swirling water current—a temporary current that extends deep beneath the ocean’s surface.”
An extreme heatwave sweeping through Southern Europe has also created a significant temperature differential between the cloudy air over the sea and the dry air over land. This may have hindered the mingling of the two fronts, contributing to the formation of the beautiful spiral shape. According to the NASA Earth Observatory, when this image was captured, temperatures in Spain and Portugal were above 40 degrees Celsius.
Interestingly, marine stratocumulus clouds typically only appear along the western coasts of vast land masses on Earth. This is because they form when cold water from the deep sea is brought to the surface by the Earth’s rotation—also known as the Coriolis effect—cooling the air above and causing moisture to condense into clouds.
The swirling clouds in the image stretch for hundreds of miles and can persist for several days. However, according to the NASA Earth Observatory, they are unlikely to release any precipitation.
