Spanish authorities fear further rainfall could hamper rescue efforts after historic flash floods in southern Valencia earlier this week.
Many streets are still blocked by piled-up vehicles and debris, in some cases trapping residents in their homes. Some areas still don't have electricity, running water, or stable telephone connections.
The death toll has now reached 202 according to authorities in Valencia after Spain's deadliest natural disaster in living memory.
Members of the security forces and soldiers are busy searching for an unknown number of missing people, many feared to still be trapped in wrecked vehicles or flooded garages. Spanish media reported that at least 40,000 people were still without power.
Chiva Mayor Amparo Fort said: “Entire houses have disappeared. We don’t know if they are with or without people.”
But there are fears the situation could yet get worse, as more storms are expected.
The Spanish weather agency issued alerts for strong rains in Tarragona, Catalonia, as well as part of the Balearic Islands.
It has issued a red alert for rainfall along the coast of Huelva in the south-west of the country and called on people in the worst-hit areas to stay at home.
The country has particularly suffered from flooding because of an almost two-year drought, meaning the dry ground was so hard that it could not absorb the rain.
Residents in hard hit areas of Valencia appealed on media for help as rescue efforts were ongoing.
"This is a disaster. There are a lot of elderly people who don't have medicine,” a resident of Alfafar, one of the most affected towns in south Valencia, told state television station TVE.
“There are children who don't have food. We don't have milk, we don't have water. We have no access to anything.
"No one even came to warn us on the first day."
Flood survivors and volunteers are engaged in the titanic task of clearing a layer of dense mud.
Residents in communities like Paiporta, where at least 62 people died, and Catarroja, have been walking miles to Valencia to get provisions, passing neighbours from unaffected areas who are bringing carry water, essential products or shovels to help remove the mud.
Juan Ramón Adsuara, the mayor of Alfafar, said the aid isn't nearly enough for residents trapped in an "extreme situation."
"There are people living with corpses at home. It's very sad. We are organising ourselves, but we are running out of everything," he told reporters.
"We go with vans to Valencia, we buy and we come back, but here we are totally forgotten."
Rushing water turned narrow streets into death traps and spawned rivers that tore through homes and businesses, leaving many uninhabitable.
Residents of affected areas have posted images of missing people on social media in the hope of getting information about their whereabouts, while others launched initiatives such as Suport Mutu, or Mutual Support, which connects requests for help with people who are offering it.
Spain's Mediterranean coast is used to autumn storms that can cause flooding, but this was the most powerful flash flooding in recent memory.
Scientists have linked it to climate change, which is also behind increasingly high temperatures and droughts in Spain and the heating up of the Mediterranean Sea.
Human-caused climate change has doubled the likelihood of a storm like this week's deluge in Valencia, according to a partial analysis issued Thursday by World Weather Attribution, a group made up of dozens of international scientists who study global warming's role in extreme weather.
