Spain recently witnessed one of the worst natural disasters in its modern history, as sudden floods caused massive and widespread destruction in the city of Valencia, located on the western coast of the country, in a rare natural weather phenomenon known as the “Dana” depression, which is an abbreviation for the scientific term “isolated depression.” In the upper layers, which caused huge amounts of wind and rain.
The Spanish city had witnessed sudden, heavy rains equivalent to an entire year’s rain, in just a few hours. This severe storm resulted in the submergence of large parts of the city, leading to the death of 155 people, while dozens are still missing. The city also recorded rainfall rates reaching 500 liters per square meter, a huge number that reflects the severity of the disaster.
This devastation also coincided with urgent calls to improve preparedness and preparedness strategies to confront natural disasters that are increasing in severity, as a result of unexpected climate fluctuations coupled with global warming, while this disaster is an emergency warning to all countries overlooking the Mediterranean basin, including Arab countries from both continents. Asia and Africa.
What is the sudden “Dana” phenomenon?
are linked “Dana” phenomenon With the change of seasons, it occurs at altitudes of up to about 9 kilometers above sea level. This phenomenon occurs when a mass of warm air collides with a stagnant mass of cold air in the atmosphere, leading to a series of atmospheric reactions that may cause heavy and violent rains and storms. Sudden and powerful.
Strong air currents in the upper layers of the atmosphere act like a belt surrounding the Earth, and sometimes these currents begin to oscillate, simulating the movement of a snake instead of remaining in a straight line. When these oscillations stop, the cold air mass is trapped in one place, as happened over the city of Valencia.
When this cold air blows over the warm waters of the Mediterranean, it causes the hot air to rise rapidly and form dense, water-laden clouds that can remain over the same area for several hours, increasing their destructive potential.
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Given that the long summer months this year were unprecedentedly severe, it was recorded The hottest day in modern history Last July, the waters of the Mediterranean Sea become a source of energy that fuels this weather phenomenon.
Although the tropical winds accompanying these phenomena may not be as violent as globally known hurricanes, the heavy rains are sufficient to cause widespread destruction, seriously threatening infrastructure.
Scientists believe that countries surrounding the Mediterranean are particularly vulnerable to these extreme weather events due to their geographical location, especially countries such as Spain, France, Italy and Greece.
Climate change…the unknown soldier
Many experts believe that the rise in temperature in the Mediterranean Sea in recent years, which has increased by 1.5 degrees Celsius since the 1980s, contributes significantly to the increase in this phenomenon.
Of course, the rise in temperature is linked to climate change and global warming, and experts believe that the seas have become more like a conveyor belt for moisture and energy, which leads to an increase in the intensity and abundance of rain when a large temperature difference occurs between the sea and the land.
On the other hand, the rapid warming of the seas and oceans, especially the Mediterranean Sea, leads to radical changes in the occurrence of the “Dana” phenomenon, as it begins early in May and continues until November, after this phenomenon was previously limited to The months of September and October.
In addition to a noticeable increase over the past six decades in the frequency of occurrence of the phenomenon by between 15% and 20%, it is expected that turbulent climate change will have a greater impact, and the region may witness the recurrence of such incidents on a larger scale within the borders of the Mediterranean basin.
