Spain floods: How could so much rain fall in such a short space of time in Valencia?

Ferocious storms in Europe are common but their pattern is changing because of sustained global warming. The deluge that hit Spain provides a glaring indication that even wealthy countries used to such extreme events are nowhere near prepared enough for what is to come.
Noting this is the deadliest weather disaster to hit Spain since 1973 fails to convey the enormity of what happened, concentrated on Valencia. It was not just about vast volumes of floodwater but also their speed and destructiveness.
A year’s rainfall within a few hours exposed failures in the national weather warning system, lack of preparedness for extreme weather and shortcomings in emergency services. Most concerning, perhaps, was the inability of people to move to safety quickly enough.
Unquestionably climate change is the key contributing factor in these extreme rain events as countries have to juggle the extremes of droughts and flooding; two sides of the same climate change coin. In Ireland it is a combination of extreme rain/flooding coinciding with saturated land.
The Mediterranean has seen the warmest surface water temperature on record with a mean temperature of 28.5 degrees in mid-August. Heat means more energy, more water vapour and more instability when the atmosphere starts to cool in the autumn.
As with regions across the planet, there are local conditions that pertain, according to the head of climate science at Met Éireann Keith Lambkin. Very warm moist air in eastern Spain is often driven upwards by colder air beneath it creates very intense rain clouds. When combined with lack of strong winds it leads to a “a conveyor belt” of torrential rain. These large storms, cut off from the jet stream, stagnate in one place.
People are familiar with the colour-coded weather warning system but the climate factor and worsening impacts is prompting a shift from “what the weather will be to impact-based warnings on what the weather will do”, Lambkin added.
This is happening at global level and within the EU, with Met Éireann leading the change in Ireland, but is not easy to implement: forecasting precisely where a rainstorm will land is a real challenge. “No model will tell you what bridge will collapse, at what time,” said Lambkin.
The UN’s World Meteorological Organisation is leading development of the Early Warnings for All initiative in response to poor warning systems in many countries, notably in Africa and South America.
People shouldn’t be dying from these kinds of forecasted weather events in countries where they have the resources to do better, said Liz Stephens, a professor in climate risks and resilience at the University of Reading.
“We have a long way to go to prepare for this kind of event, and worse, in future. Limiting damage and loss of life from extreme weather is only possible through adapting our infrastructure and early warnings to a more dangerous world and, crucially, by rapidly and massively cutting our greenhouse gas emissions, which is the crux of the problem.”
Human-caused climate change intensified all of the 10 deadliest extreme weather events of the past 20 years and contributed to more than 570,000 deaths, a study by the World Weather Attribution group at Imperial College in London, published on Thursday, found. It highlights how climate change is already incredibly dangerous at 1.3 degrees of warming.
When it comes to rainfall every extra degree of warming gives the atmosphere another 7 per cent of carrying capacity for water. With Europe warming at twice the rate of any other continent that means the devastation of Valencia, unfortunately, will soon be repeated elsewhere.