Why is Spain flooding?- Molly N

Why is Spain flooding?- Molly N

The devastating floods in Spain are currently a primary focus in the news. However, the media generally focusses less on why this is occurring, so to put my Geography A level to use (and do something other than colouring in), I have outlined some of the key factors causing this extreme flooding.

However, firstly, here are some quick figures to show that these aren’t just any ordinary floods: Valencia received a year’s worth of rain in just 8 hours, over 205 people have died and there are rapidly rising cases of missing peoples. Some sources say it’s the worst flash flood event in recent memory within Spain.

The European Space Agency explains that the extreme rainfall was a result from a “low-pressure weather system isolated from the jet stream”. If that sounds confusing, don’t worry, because I was also confused. So while being a wakeup call that I may need to do some more revision, I have broken it down.

“Low Pressure” refers to rainy conditions, and is the opposite of High Pressure. More specifically, it was convectional rainfall. This is where cold air moves over warm ocean waters, in this case, the Mediterranean Sea. As the air heats up, it rises (as it is less dense than cold air), carrying with it the moisture. The water condenses into clouds and ultimately results in rainfall. Occurring in Spain, these clouds lasted hours and released hailstorms as well as rainfall.

“Jet Streams” are like rivers of air in the atmosphere that move weather systems across the globe. The immediate cause of the intense rainfall in Spain was a lower-pressure storm system that migrated from an unusually wavy jet stream. These often occur over Spain, and are so frequent that they have been given the name ‘DANAs’.

However, recently the rainfall has been unusually intense. This intensity is connected to climate change, which has increased sea temperatures (in turn increasing convectional rainfall) and warmed up the air, meaning the atmosphere can hold more moisture and so causing more rainfall at a singular time. Climate change also changes the jet streams, hence moving and destabilising weather conditions.

Clouds showing a jet stream over Canada (Wikipedia)

If all of those causes weren’t enough, Spain had battled with prolonged droughts in 2022 and 2023, which hardened the ground and so prevented water from infiltrating into the soil. This caused water to run off into rivers, and combined with the intensity of the rainfall, this overflowed river banks and drainage canals, leading to flash floods.

Overall, the extreme flooding in Spain was caused by a low pressure system migrating from its jet stream. Climate change played a role in increasing convectional rainfall and changing the jet streams. The impacts of the rainfall were exacerbated by previous droughts, and some sources also mention poor urban planning and governance.

Main Image: latimes