What you need to know about Spain’s unprecedented floods that have killed at least 158 ​​people

MADRID – Flash flooding caused by heavy downpours in eastern Spain on Tuesday swept away everything in its path in a matter of minutes. Before they could react, people were trapped in cars, houses and businesses. Many died and thousands lost their livelihoods.

two days later authorities discovered 158 bodies — 155 in the eastern region of Valencia alone, two in Castilla-La Mancha and one in Andalusia — and the search continues for an unknown number of missing people.

People began clearing thick layers of mud that covered houses and streets littered with debris, facing power and water outages and shortages of some basic goods. Some of the cars that were washed away in piles or crashed into buildings still had bodies waiting to be identified.

Here are a few things to know about Spain’s worst storm on record:

What happened

The storms centered over the Magro and Turia river basins, and in the Poyo river bed created walls of water that overflowed the banks of the river, catching people off guard as they went about their daily lives, with many returning home from work on Tuesday evening.

In the blink of an eye, muddy water covered roads, railways and entered homes and businesses in villages on the southern outskirts of the city of Valencia. The drivers, converted into boats, had to hide on the roofs of the cars, while the residents tried to take cover on high ground.

The downpour was amazing. Spain’s National Meteorological Service reported that the hard-hit region of Chiva received more rain in eight hours than in the previous 20 months. calling the flood “extraordinary”.

As authorities sent cellphone alerts warning of the severity of the phenomenon and asking them to stay at home, many were on the road, working or covered in water in low-lying areas or garages that had become death traps.

Why did these large-scale flash floods occur?

Scientists trying to explain what happened see two possible connections with climate change caused by human activity. First, warmer air holds and then sheds more rain. Another is possible changes in the jet stream—the river of air above the ground that moves weather systems around the globe—that creates extreme weather.

Climatologists and meteorologists said the immediate cause of the flooding was a low-pressure storm system that moved from an extremely wavy and stalled jet stream. That system just stood over the region and rained down. This happens often enough that in Spain they are called DANA, the Spanish abbreviation for the system, meteorologists say.

In addition, there is the unusually high temperature of the Mediterranean Sea. Mid-August saw the highest surface temperature on record at 28.47 degrees Celsius (83.25 degrees Fahrenheit), according to Carola Koenig of Brunel University London’s Flood Risk and Resilience Centre.

The extreme weather comes after Spain struggled with prolonged droughts in 2022 and 2023. Experts say that drought and flood cycles are increasing with climate change.

Has this happened before?

Spain’s Mediterranean coast is used to autumn storms that can cause flooding, but this episode was the worst flash flood in recent memory.

Elderly people in Paiport, the site of the tragedy, said Tuesday’s flooding was three times worse than the 1957 flood, which killed at least 81 and was the worst in the tourism region’s history. This episode led to the diversion of the Turia River, which meant that a large part of the city was spared from these floods.

In the 1980s, Valencia experienced two more major DANAs: one in 1982, which killed around 30 people, and another five years later, which broke rainfall records.

This week’s flash floods are also the deadliest natural tragedy in Spain’s history, surpassing the flood that swept away a campsite along the Gallego River in Biescas in the northwest, killing 87 people in August 1996.

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Seth Borenstein of Washington, DC contributed.