Although we used to call it a cold drop, now by the name of DANA we know the Isolated Depression at High Levels and it has caused havoc and floods in many parts of Spain.
It is a meteorological phenomenon that gives rise to heavy rains, like those that have been seen these days in various parts of Spain.
What does DANA mean and why is it produced?
We are talking about the collision of a cold air mass in height with warm air from the surface, which then gives rise to showers and storms.
This phenomenon usually appears at the beginning of autumn and spring in the western Mediterranean in certain areas of Spain. Especially in the Mediterranean and in the Balearic Islands, but, as we have seen, this year has taken place much earlier because it is still missing for the beginning of autumn.
Experts in this field are not sure that it is due to climate change because it is something that has yet to be corroborated, but they are clear that this type of phenomenon will be increasingly important in the world.
It occurs as a result of a cold polar air front (jet stream) creeping over western Europe at high altitudes (typically 5-9 km). When colliding with the warmer and more humid air of the Mediterranean Sea , this is when these intense storms occur.
Where does this name come from?
The origin of the cold drop appears in 1886 in the German school, with the idea of Kaltlufttropfen, which is translated as a drop of cold air as we know. The definition given was the following: “a marked depression in height, without reflection on the surface, in the central part of which is the coldest air.”
According to the RAE, the cold drop is the mass of air that emerges from a very cold current and descends on another of hot air, producing large atmospheric disturbances accompanied by very intense precipitation.
In general, and although the name cold drop is more popular, the AEMET has long explained that it is better to use DANA because the former is somewhat old and the term dana in Anglo-Saxon is “cut-off low” , actually much more accurate and realistic .
In these days, AEMET has already announced that at points of, practically, all the autonomous communities can fall between 15 and 20 l / m2 in less than an hour, even 30 l / m2 and that could be more pronounced in the interior of the Region of Murcia, interior of the Valencian Community, points of the Community of Madrid, east and north of Castilla-La Mancha, east of Castilla y León, large areas of Aragon and also in Navarra.
