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

MADRID – Within minutes, flash floods caused by heavy rains in eastern Spain on Tuesday swept away everything in their path. With no time to respond, people were trapped in vehicles, homes and businesses. Many died and thousands saw their livelihoods shattered.

Two days later, authorities have recovered 158 bodies – 155 in the eastern region of Valencia alone, two in Castilla La Mancha and one in Andalusia – and continue to search for an unknown number of missing people.

People have begun clearing thick layers of mud that covered homes and streets full of rubble, while dealing with power and water cuts and shortages of some basic goods. Bodies still lay in some vehicles that had been washed into piles or crashed into buildings by the water.

Here are a few things you need to know about Spain’s deadliest storm in living memory:

What happened?

The storms concentrated over the Magro and Turia river basins and produced walls of water in the Poyo riverbed that overflowed the banks of the river, leaving people unaware as they went about their daily lives, with many came home from work on Tuesday evening.

In an instant, the muddy water covered roads, railways and entered homes and businesses in villages on the southern outskirts of the city of Valencia. Drivers, with their vehicles converted into boats, had to take shelter on car roofs, while residents tried to take refuge on higher ground.

The downpour was breathtaking. Spain’s national weather service said it rained more in eight hours in the hard-hit town of Chiva than in the previous 20 months. called the flood “extraordinary.”

When authorities sent the alert to mobile phones warning of the severity of the phenomenon and asking them to stay at home, many were on the road, at work or under water in low-lying areas or garages, which became a death trap.

Why did these massive flash floods happen?

Scientists trying to explain what happened see two possible connections man-made climate change. One of these is that warmer air holds more rain and then transports it away. The other is possible changes in the jet stream – the river of air over land that moves weather systems around the world – that are producing extreme weather.

Climate scientists and meteorologists said the direct cause of the flooding is a cut-off lower-pressure storm system that migrated from an unusually wavy and stalled jet stream. That system simply parked over the region and dropped rain. This happens often enough that in Spain they call them DANAs, the Spanish abbreviation for the system, meteorologists say.

And then there is the unusually high temperature of the Mediterranean Sea. By mid-August it had the warmest surface temperature on record, at 28.47 degrees Celsius (83.25 degrees Fahrenheit), said Carola Koenig of the Center for Flood Risk and Resilience at Brunel University of London.

The extreme weather conditions came after Spain suffered prolonged droughts in 2022 and 2023. Experts say so 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 most powerful flash flood in recent history.

Elderly people in Paiporta, at the center of the tragedy, claim Tuesday’s floods were three times worse than those of 1957, which killed at least 81 and were the worst in the tourist eastern region’s history. That episode led to the rerouting of the Turia watercourse, which spared a large part of the city from these floods.

Valencia suffered two other major DANAs in the 1980s: one in 1982, with around thirty deaths, and another five years later, which broke rainfall records.

This week’s flash floods are also Spain’s deadliest natural tragedy in living memory, 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 from Washington DC contributed.