These days a DANA has passed, and is still passing through Valencia and many questions arise : What exactly is a DANA? How do they form? Do they have to do with climate change or have they always happened?
Here we answer all these questions so you can better understand what has happened in Valencia these days.
What is a DANA and how does it form?
Let’s start with the main thing. The acronym DANA stands for Isolated High Level Depression. An atmospheric depression is an area where the pressure is low and the wind circulates counterclockwise, getting stronger and stronger. When this occurs at the surface, for example, it can cause squalls and strong gusts of wind.
When a DANA appears, a mass of cold air is formed at a high altitude, near 9,000 meters, and the intensity of the wind in these air masses can cause an isolated depression. Hence the acronym. In summary, a DANA forms at high levels when a large polar air mass is in circulation and a trough is formed.
Despite its development at very high altitudes, the DANA can affect the surface and other areas of the atmosphere, and when it collides with a warmer air mass, such as those we have in the Mediterranean, is when phenomena such as those of these days originate.
Effects of climate change
DANAs, or cold drops, as they are popularly known, usually form in late summer and early autumn, as this is when sea temperatures are at their highest and, as we have said, the cold air mass needs to collide with a warmer one to cause rain, storms and strong winds.
So, does climate change have something to do with it? Yes and no. Although these types of phenomena are not new and have always happened, it is now, when water temperatures are higher, that they are generated more and with more intensity.
Therefore, the effects of climate change are beginning to be felt, since, although this DANA has not been caused by it alone, the increase in temperatures has made it worse and the rains have been more torrential and devastating.