Spain has been shaken in the last hours by a certain climatic phenomenon: DANA, an isolated depression at high levels. This phenomenon has caused floods in different parts of the country.
DANA occurs when an isolated atmospheric depression occurs at high levels as a result of the collision of a mass of cold air at altitude with warm air at the surface, resulting in heavy rain and storms.
In the case of Spain, floods caused significant material damage in Catalonia, where a motorway had to be closed due to advancing water. The earthquake was also felt by the Valencian Community and the alarm continued in cities such as Madrid, Zaragoza, Cuenca, Guadalajara, Teruel and Pamplona.
Strictly speaking, DANA can be defined as “a low pressure system that manifests itself particularly in the middle and upper layers of the troposphere,” according to the Spanish State Meteorological Agency (Aemet).
“To understand its formation, you have to look at the polar plane. It is a very intense wind current at high levels of the troposphere that rotates from west to east and separates the cold polar air (which is north of this stream) from the warm equatorial air (south of the stream).”
“The ripples of the polar jet, like meanders of a river, and the ripple is sometimes so intense that the wave itself suffocates and separates from the polar jet: at that moment there is a kind of cold air surrounded by warmer air, we already have a DANA formation,” Emmett added.
It is remarkable that this phenomenon has grown globally in the last half century, according to the records of the American Meteorological Society.
Regions such as southern Europe, the US east coast, the northeastern Pacific, and northwestern North America can be susceptible to its consequences, as are southern Asia, Australia, New Zealand, and South America.