At least 51 people have been killed in flash floods sweeping the eastern Spanish region of Valencia following torrential rains on Tuesday that left roads and towns under water, local authorities said on Wednesday.
Dozens of videos shared on social media overnight appeared to show people trapped by the floodwaters, with some climbing into trees to avoid being swept away.
Torrential rains caused by a cold front moving across southeastern Spain flooded roads and towns on Tuesday, prompting authorities in the worst-hit areas to advise citizens to stay at home and avoid all non-essential travel.
Carlos Mazon, the regional leader of Valencia, told a press conference some people remained isolated in inaccessible locations.
"If (emergency services) have not arrived, it's not due to a lack of means or predisposition, but a problem of access," Mazon said, adding that reaching certain areas was "absolutely impossible".
Spain's state weather agency AEMET declared a red alert in the eastern Valencia region and the second-highest level of alert in parts of Andalusia in the south, where a train derailed due to the heavy rainfall, although no one was injured.
Footage showed firefighters rescuing trapped drivers amid heavy rain in the Valencian town of Alzira and flooded streets with stuck cars.
Scientists say extreme weather events are becoming more frequent due to climate change. Meteorologists believe the warming of the Mediterranean, which increases water evaporation, plays a key role in making torrential rains more severe.
AEMET expected Valencia to take the brunt of the storm, with forecasts of more than 90 mm (3.5 inches) of rain in less than one hour, or 180 mm in under 12 hours.
Schools, courthouses and other essential services were suspended in Carlet and some other nearby towns in the Valencia region.
Local emergency services requested the help of UME, a military unit specialised in rescue operations, in the area of Utiel-Requena, where farmers' association ASAJA said the storm was causing significant damage to crops.
The storm first struck Andalusia. In El Ejido, a Mediterranean city known for its sprawling greenhouses, a hailstorm broke hundreds of car windscreens, flooded the streets and damaged the mostly plastic greenhouse infrastructure.
In Alora, also in Andalusia, the Guadalorce river overflowed and 14 people there had to be rescued by firefighters, authorities said. Alora topped AEMET's ranking on Tuesday with 160 mm of rainfall.