Spain deployed more than 1,000 troops to help with rescue efforts on Wednesday, but many crews remain cut off from towns by flooded roads and downed communication and power lines.
The European Union’s chief, Ursula von der Leyen, said it had activated its Copernicus satellite system to help co-ordinate Spanish rescue teams. Other European neighbours have also offered to send reinforcements.
Spain’s Defence Minister Margarita Robles had said earlier on Wednesday the flooding across the region was “an unprecedented phenomenon”.
The downpour eased in the country’s central-east on Wednesday, but weather officials warned the rains were moving north-east to the Catalonia region. Weather warnings have also been issued across several other parts of the country, urging people to brace for floods and take shelter.
Many factors contribute to flooding, but a warming atmosphere caused by climate change makes extreme rainfall more likely.
Weather researchers have identified the likely main cause of the intense rainfall as a “gota fria” – a natural weather event that hits Spain in autumn and winter when cold air descends on warmer waters over the Mediterranean.
However, the increase in global temperatures had led to the clouds carrying more rain, scientists told the BBC.
“With every fraction of a degree of fossil fuel warming, the atmosphere can hold more moisture, leading to heavier bursts of rainfall,” said Dr Friederike Otto, from Imperial College London, who leads an international group of scientists who try to understand the role that warming plays in these type of events.
“No doubt about it, these explosive downpours were intensified by climate change.”
The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.