The toll stands at 217 dead -- almost all in the eastern Valencia region -- with the country dreading the discovery of more corpses as an unknown number of people remain missing.

National weather service AEMET announced the end of the emergency for Valencia but torrential rain struck Catalonia, where residents received telephone alerts urging the utmost caution.

Barcelona's El Prat airport, Spain's second busiest, said 50 flights were cancelled or delayed and 17 diverted on Monday, while the city closed some flooded metro stations and regional trains were suspended.

Images on social media showed cars ploughing through flooded roads in the Barcelona suburbs of Castelldefels and Gava and bare-footed travellers wading through water that had seeped into El Prat.

Spain also grappled with the aftermath of an extraordinary outburst of popular anger in which crowds heckled and hurled mud at King Felipe VI, Queen Letizia and Prime Minister Pedro Sanchez.

The Civil Guard has opened an investigation into the chaos in the ground-zero town of Paiporta that cut short their visit on Sunday, Interior Minister Fernando Grande-Marlaska told public broadcaster TVE.

He blamed "marginal groups" for instigating the violence where mud spattered the monarchs' face and clothes and a window of Sanchez's car was broken.

- 'We were abandoned' -

The incident underscored growing anger at the authorities' preparation for and reaction to the catastrophe.

Experts have questioned the warning systems that failed to alert the population in time and the speed of the response.

"They were saying 'alert for water', but they should have said it was a flood," Teresa Gisbert, 62, told AFP in the destroyed town of Sedavi, saying she had "lost everything".

Thousands of soldiers, police officers, civil guards and firefighters spent a sixth day distributing aid and clearing mud and debris to find bodies.

But relief works only reached some towns days after the disaster and in many cases volunteers were the first to provide food, water, sanitation and cleaning equipment.

"We shouldn't romanticise it: the people saved the people because we were abandoned," said Jorge, 25, a resident of the town of Chiva where the royals cancelled their visit on Sunday.

Divers on Monday concentrated their search for missing bodies in garages and a multi-storey car park in the town of Aldaia.

The storm caught many victims in their vehicles on roads and in underground spaces such as car parks, tunnels and garages where rescue operations are particularly difficult.

Local authorities in Valencia extended travel restrictions for another two days, cancelled classes and urged residents to work from home to facilitate the work of the emergency services.

- 'Consequences of inaction' -

The unity that bound Spain's polarised politics when the tragedy struck started to fray as attention turned to those responsible for handling the crisis.

Far-right party Vox slammed Spain's "failed" state, blaming Sanchez for the slow deployment of troops and "demonising" volunteers. The hard-left Podemos demanded the resignation of the Valencia region's conservative leader Carlos Mazon.

Sanchez has said now is not the time to scrutinise the management of the disaster during urgent rescue and reconstruction work.

The main opposition Popular Party urged the left-wing government to go further by declaring a national emergency and approving aid packages for individual citizens.

Storms coming off the Mediterranean are common during this season. But scientists have warned human-induced climate change is increasing the ferocity, length and frequency of extreme weather events.

"Politicians haven't acted on climate change, and now we're paying the consequences of their inaction," environmental activist Emi, 21, told AFP in Chiva.