(CN) — At least 95 people were killed in catastrophic flash flooding that inundated the Spanish province of Valencia and nearby regions Tuesday evening.
A severe cold snap unleashed torrential rains, which continued to pummel parts of Spain on Wednesday. Spain declared three days of national mourning as the magnitude of the flooding grew, making it one of the country’s worst natural disasters in decades.
Flash flooding occurred with little warning from emergency authorities and turned streets into waterways, washed out bridges, tore up roads and left scores of people stranded with their vehicles, in trees and atop buildings.
“Everyone was expecting some rain but not much more than that,” said Alessandro Prestianni, a 32-year-old Italian who works in a coffee shop at a bed and breakfast in central Valencia. He was reached by telephone. “We didn’t expect all this chaos, this hell.”
By Wednesday, the scale of the disaster became clear, he said, as he served customers.
“Everyone told me a story: There was someone who hadn’t heard from a grandmother; someone who hadn’t heard from a mother; someone who lost all his belongings; someone who lost his house.”
The death toll quickly rose from 13 early Wednesday to more than 70 by the afternoon and then to 95 by Wednesday night. The number of deaths was expected to rise as search and rescue crews worked to reach hard-hit villages, towns and suburbs of Valencia. Severe flooding also was reported in the nearby provinces of Cuenca and Albacete. Dozens of people were reported missing.
“We still do not have the full picture of the effects and damage because there are areas that have not yet been accessed,” said Pedro Arcos, a medical epidemiologist with a disaster research unit at the University of Oviedo, in an email.
The flooding left piles of washed-away vehicles, cut off roads and railways, left thousands of people displaced and caused widespread power outages. Rail traffic between Valencia, Madrid and Barcelona was suspended Wednesday. The damage was extensive with reports of widespread flooding of homes, businesses and infrastructure.
Spanish Prime Minister Pedro Sanchéz pledged the utmost help and he expressed “solidarity and affection” for those who lost family members
“We will help you for as long as it takes. We will not leave you alone,” he said. “All of Spain is with you. For those who at this moment are still looking for their loved ones, the whole of Spain weeps with you.”
The flash flooding was attributed to a cold snap that saw a collision of chilly upper-level air with warm, moist air from the Mediterranean Sea, according to a University of Oviedo report.
“Climate change has intensified these phenomena, leading to more frequent and severe storms, particularly in September and October,” the report said.
Prestianni said torrential rains quickly flooded suburban areas and towns in the vicinity of Valencia Tuesday evening. He described how a colleague left to go home Tuesday evening and an hour later sent him a video in which he was stranded in floodwaters atop his vehicle on a highway out of Valencia.
“They went to rescue him and right when they saved him, in that exact moment, his car was swept away by the water,” Prestianni said.
Emergency officials faced scrutiny for not adequately warning citizens about the flood threat. An alert was sent at 8 p.m. to telephones warning people to not leave their homes, but by then hundreds of people were already stranded, according to Spanish media reports.
Carolina Martí Llambrich, a coastal researcher at the University of Girona, said a cold air pocket at high altitude, a weather pattern known as a “dana,” triggered the flooding as “humid northeast winds from the still-warm waters of the Mediterranean” crashed against the mountains of Valencia.
“When this warm, moist air collided with the cold dana air, it caused sudden condensation, resulting in heavy rainfall,” she said in an email.
Heavy rains and powerful winds, including tornadoes, lasted for over eight hours over Spain’s eastern coast. She said rainfall ranged between 11.8 inches and 19.7 inches and that 6.2 inches fell in just one hour in places.
The region’s mountainous topography with its steep rivers and streams — most of which are dry riverbeds called “barrancos” — funneled huge amounts of water rapidly into the plains surrounding Valencia.
She said a normally dry barranco turned into a violent river “that swept away everything in its path in mere minutes.”
Adding to the problems, storm-driven sea surge on the coast prevented the floodwaters from emptying into the sea and that led to extensive flooding along coastal areas, she said.
Arcos, the expert at the University of Oviedo, said climate change is making storms caused by cold snaps much worse. This cold snap was one of the worst in recent decades, he said.
“These extreme climatic episodes of very high intensity used to occur only every five or 10 years in Spain, but climate change is now making them more frequent and intense,” he said.
He said Spain will need to step up efforts to prevent future floods by upgrading its flood management systems, for instance by improving river barriers and drainage systems.
Valencia has long dealt with flooding which at times has caused catastrophic damage. On Oct. 14, 1957, a flood killed about 81 people and devastated the city of Valencia when the Turia River burst its banks, according to a report from the University of Oviedo’s disaster unit.
In that flood’s aftermath, the Turia River was diverted away from the city center and its former riverbed was turned into a park, the Turia Garden, a project that helped prevent flooding in the city.
But outside the city, flooding remains a persistent problem. The province has been hit by major floods in 1982, 1987, 1996, 2007, 2016 and 2019. Intense rainfall in Valencia, a region known for its mostly sunny and dry weather, is mostly associated with cold snaps in September and October. In 1996, more than 20 inches of rain dropped on the region and in 1982 more than 29 inches of rain caused a dam breach and several deaths.
“These events highlight a troubling increase in the frequency and severity of floods impacting the region,” the report said.
Flooding has been made worse by rapid urban growth and inadequate drainage systems that have not kept pace with development and climate change, the report said.
“This increases surface runoff during heavy rain events, overwhelming existing drainage systems,” it said.
Martí Llambrich said the metropolitan area of Valencia has become densely populated in the past 50 years with much of the growth taking place on flood-prone lands.
Courthouse News reporter Cain Burdeau is based in the European Union