At least four people were killed and others were stranded on rooftops as heavy rain and floods battered Spain's Mediterranean coast, state broadcaster RTVE reported on Monday.
Rescue crews freed dozens of people who had been stranded since early morning, some on rooftops, in flooded buildings, or in vehicles.
Many roads, houses and campsites were underwater in the provinces of Valencia and Alicante. Floods also hit the Balearic Islands of Majorca and Ibiza.
Rescue operations used helicopters and boats, and even a surfboard: Police video showed a 93-year-old woman being brought to safety on one in Gandia.
The regional government declared the second-highest emergency level. Classes were suspended in more than 40 municipalities in the provinces of Valencia and Alicante.
Initially, authorities imposed a curfew of several hours for 145 municipalities with more than 800,000 residents in total.
By the afternoon, the curfew applied to only eight municipalities. However, several places remained cut off from the outside world due to the flooding.
The situation was particularly serious in the coastal town of Oliva, about 70 kilometres (43.5 miles) south of the provincial capital Valencia, where two bodies were recovered on Monday.
Storm system Adam had already caused chaos on the Spanish mainland at the weekend with extreme rainfall. Two people died: One woman in Sagunto in Valencia province, and another woman in Cabrera de Mar in Catalonia.
According to Mayor Yolanda Pastor, about 2,000 people were evacuated from seven campsites in Oliva.
"Many people are still trapped in their homes by the floodwaters," the mayor told the private broadcaster Antena 3. She said some people had climbed onto their roofs to escape.
A spokesperson for the emergency services said all people in life-threatening situations in Oliva had already been brought to safety.
Authorities in the hardest-hit areas in the south of Valencia province and the north of Alicante province urged people to stay in their homes where possible. The coastal regions of La Safor in Valencia and Marina Alta in Alicante were particularly affected.
According to Spain's state weather service AEMET, more than 530 millimetres of rain was recorded in Oliva within 24 hours. In the municipality of Pego in Alicante, just over 620 mm fell.
On Mallorca, the situation remained calm despite the highest red alert level declared for the night. Rescue services registered only three minor incidents: two fallen trees and a risk of collapse, which has since been resolved.
A total of 16 incidents were reported on the Balearic Islands, 11 of them on Ibiza and two on Formentera. Schools on all the islands had cancelled classes for Monday as a precaution.
Over the course of Monday, the rain in Valencia and Alicante and on the Balearic Islands was expected to gradually ease and move further north into Catalonia.
Almost two years ago, the Valencia region was hit by a devastating flood disaster that killed more than 220 people.
