Why was Valencia flooding so deadly, did warning texts come too late and what’s the climate link?

Why was Valencia flooding so deadly, did warning texts come too late and what’s the climate link?

More than 200 people have been killed in southern and eastern Spain following deadly flash flooding.

That number is expected to rise further as the search continues for dozens still missing, some regions yet to report their victims and more rain forecast to hit some of the worst affected parts of the country.

In some areas, a year’s worth of rain fell in just eight hours on Tuesday. Spain’s National State Meteorological Agency (AEMET) says in the Chica area of Valencia an “extraordinary” 491 litres per square metre accumulated in eight hours.

Inundated after the heavy rainfall, people were left trapped in their homes, cars swept away and bridges buckled under the force of the water. Rescue crews have been left fighting to reach areas cut off by the destruction and local residents have been queuing for vital supplies.

On Friday, Spain deployed hundreds of troops to Valencia to help with the emergency response.

People stand in front of their houses affected by floods in Utiel, Spain.
People stand in front of their houses affected by floods in Utiel, Spain. - AP Photo/Manu Fernandez

“This is the dramatic reality of climate change,” European Commission President Ursula von der Leyen said on Wednesday, adding that extreme weather phenomena have become the “new normal”.

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“And we must prepare to deal with it, all across our Union, and with all tools at our disposal.”

Is climate change to blame for deadly flooding in Valencia?

“The images and videos from south-eastern Spain show the power of water at its most furious,” says Dr Linda Speight, lecturer at the University of Oxford’s School of Geography and the Environment (SoGE).

“Unfortunately, these are no longer rare events. Climate change is changing the structure of our weather systems creating conditions where intense thunderstorms stall over a region leading to record-breaking rainfall – a pattern that we are seeing time and time again.”

Climate scientists and meteorologists have blamed the flooding on something called a ‘cut-off low pressure storm system’ that had migrated from an unusually wavy, stalled jet stream. This system then got stuck over the region, pouring down a year’s worth of rain in eight hours.

It is a natural weather event that usually hits Spain in Autumn and Winter. This phenomenon is so common it has its own acronym, a DANA or Depresion Aislada en Niveles Altos.

Unusually warm sea surface temperatures, made much more likely by human-caused climate change, and our warming atmosphere, however, directly impact how much rain these storms can hold. The ground in many parts of eastern and southern Spain has also been left less able to effectively absorb rainwater following severe drought.

Cars are swept away by the water, after floods preceded by heavy rains caused the river to overflow its banks in the town of Alora, Malaga, Spain.
Cars are swept away by the water, after floods preceded by heavy rains caused the river to overflow its banks in the town of Alora, Malaga, Spain. - AP Photo/Gregorio Marrero

“No doubt about it, these explosive downpours were intensified by climate change,” explains Dr Friederike Otto lead of World Weather Attribution at the Centre for Environmental Policy, Imperial College London.

A rapid partial analysis done by this group of international scientists suggests that human-caused climate change made Spain's rainfall around 12 per cent heavier. It also found that that the weather event the region experienced was twice as likely.

Though it isn't a full, detailed attribution study, they say climate change is the most likely explanation for the extreme downpours.

“With every fraction of a degree of fossil fuel warming, the atmosphere can hold more moisture, leading to heavier bursts of rainfall. These deadly floods are yet another reminder of how dangerous climate change has already become at just 1.3°C of warming,” Otto adds.

She highlights that just last week, the UN warned the world was on track to experience up to 3.1°C of warming by the end of the century.

“At COP29 global leaders really need to agree to not only reduce, but stop burning fossil fuels, with an end date. The longer the world delays replacing fossil fuels with renewable energy, the more severe and frequent extreme weather events will become.”

Could Valencia have been better prepared for extreme weather?

Local authorities have been criticised for failing to issue timely warnings about the potential dangers of the storm.

Valencia’s government has admitted it only sent out text messages warning residents of the catastrophe eight hours after floods were first reported and 10 hours after AEMET issued a warning about “extreme danger” in the region.

This brief message sent just after 8pm on Tuesday came too late for many who were already trapped in their homes, in shops or in their cars on the streets as the deadly flooding hit.

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Hannah Cloke, a hydrology professor at the University of Reading, says it is “appalling” to see so many people dying in floods in Europe when forecasters had predicted extreme rainfall and issued warnings.

People pick up goods in a supermarket affected by the floods in Valencia, Spain.
People pick up goods in a supermarket affected by the floods in Valencia, Spain. - AP Photo/Manu Fernandez

“The tragedy of people dying in cars and being swept away in streets is entirely avoidable if people can be kept away from rising flood water. This suggests the system for alerting people to the dangers of floods in Valencia has failed, with fatal consequences.

“It is clear people just don't know what to do when faced with a flood, or when they hear warnings.”

The World Meteorological Organization said on Friday that effective flood warning systems could haved helped avoid the level of destruction that occurred in Valencia.

“We do need to ensure that the early warnings reach those who need them,” WMO official Clare Nullis told a regular UN briefing.

“We need to ensure that early warnings lead to informed early action.”

Nullis declined to comment on if authorities were too slow in issuing warnings to residents about the floods. She said it was something "Spanish authorities need to examine".