The arrival of a DANA in Spain once again puts several areas of the country on alert due to the risk of intense rains and storms. This meteorological phenomenon, technically known as Isolated Depression at High Levels, is one of those responsible for some of the most intense precipitation episodes recorded on the peninsula.
The State Meteorological Agency (AEMET) has warned that the new DANA crossing Spain may cause strong showers, snowfalls in mountain areas, and a drop in temperatures for several days.
What DANA means
The term DANA corresponds to the acronym for Isolated Depression at High Levels. It is a pocket of very cold air located in high layers of the atmosphere that separates from the general circulation.
When that cold air comes into contact with warmer and more humid air at the surface, a very unstable atmosphere is generated, which favors the formation of intense storms and heavy rainfall.
This phenomenon can develop at any time of the year, although it is more frequent in autumn and spring.
Why a DANA causes such heavy rains
The DANAs can generate intense rains because they combine several atmospheric factors that favor instability:
- Cold air at altitude, which increases the formation of storms
- Warm and humid air at the surface
- Ascending air movements, which facilitate the formation of clouds with great vertical development
When these elements coincide, very intense downpours can occur in a short time, sometimes accompanied by storms, hail, or strong gusts of wind.
The most affected areas are usually those of the Mediterranean
In Spain, DANAs usually affect with greater intensity the regions near the Mediterranean, where the warm and humid air favors the formation of storms.
Among the areas that usually register the most intense episodes are:
- Valencian Community
- Murcia
- Balearic Islands
- Catalonia
- Eastern Andalusia
However, depending on its trajectory, the instability can extend to a large part of the peninsular territory.
A difficult phenomenon to predict
One of the aspects that most worries meteorologists is that DANAs can be very difficult to predict with accuracy.
Unlike other storms, its displacement can change rapidly, which causes the intensity of the rains and the most affected areas to vary in a short time. For this reason, AEMET constantly updates its forecasts when a DANA forms, especially if there is a risk of intense rainfall.