Prime Minister Pedro Sánchez said emergency services were “working tirelessly” to protect people and restore “normality” to places affected by flooding “as soon as possible”.
One of the worst-hit areas was Alcanar, a town 200 kilometres (160 miles) south of Barcelona, where huge torrents of fast-moving water surged through the streets, sweeping away everything in its path.
Firefighters and local residents used brooms and hoses on Thursday to clear the streets of mud, tree branches and other debris.
“It seemed like the world was ending,” Alcanar mayor Joan Roig told radio Rac 1, adding the town was “devastated”.
Regional authorities relocated 83 people into hotels or a local sports facility.
The storm knocked out power to 10,000 homes in the northeastern region of Catalonia but as of Thursday only 200 residences lacked electricity, a spokesman for power firm Endesa said.
Heavy rain also fell in Spain’s northern Navarra region and in Madrid, forcing the closure on Wednesday of several metro stations due to flooding.
The Toledo province municipalities of Cobisa, Argés and Polán also bore the brunt of the torrential rain in Spain this week, where the force of the floods knocked down the wall of one local who shouted “Help!” desperately as a wave of mud and debris approached his home.
Emergency services rescued several people from cars that were caught in rising waters but no fatalities were reported.
Much of central and northern Spain, along with the Balearic Islands, remained on alert for storms on Thursday, according to the national weather office, Aemet.
The Murcia town of Aguilas was among the most affected by the floods on Thursday, having already experienced similarly destructive weather in March 2021.
The heavy rain that’s caused chaos throughout much of Spain over the past days is expected to mostly subside on Friday.
Torrential rains are becoming ever more frequent in Spain, with flooding causing seven deaths in the southeast in September 2019, while another storm left 13 dead in the Balearic island of Mallorca a year earlier.
Experts say global warming has increased the amount of water vapour in the atmosphere, making episodes of intense rainful more likely to happen, raising the risk of flooding.