"It has been raining non-stop for 10 hours...And the result is what you see," the 49-year-old warehouser worker told AFP in Ribarroja del Turia, pointing to flooded streets caked in mud.

"We are cut off, you can't reach parts of the town. The roads are all cut, bridges are cut."

Rellan lives in a town on the outskirts of the Mediterranean coastal city of Valencia, whose region bore the brunt of the damage and more than 70 deaths announced nationwide following the torrential rains.

The local Turia river was a roaring torrent of swollen, brownish water that was flowing close to the top of a main bridge when AFP visited on Wednesday.

Stranded motorists loitered outside their vehicles as a huge tailback snaked along the motorway leading out of the town during severe disruption to road transport.

"It had been a long time since this happened and we're scared," said Esther Gomez, a Socialist town councillor in Ribarroja del Turia.

We went from "being in a place where nothing is happening to there being such a huge flood" in a matter of minutes, the 57-year-old told AFP.

The inaccessibility of flooded roads and damage to communications and power infrastructure have complicated an already herculean task for the rescue services.

"The emergency and security services were also overwhelmed, because so many places were affected that they couldn't get to all the places," Gomez said as she remembered a chaotic night.

The sudden surge of the waters in nearby streams flooded the town's industrial estate and left workers stuck there overnight "with no chance of rescuing them", she said.

The same fate befell other areas of the Valencia region, including the village of L'Alcudia which resident Eva Sanz said was "destroyed" in the floods.

The river overflowed "in three or four minutes. In a very short time the whole panorama changed completely", she told Spanish public broadcaster TVE.

"The fright from last night is worse than the clean-up now... we were very scared."

The storm dumped 230 mm of rain on the Valencia region town of Utiel on Tuesday -- three times the previous daily record, according to national weather agency AEMET.

That represented a quantity of water almost six times greater than what the area receives on average for the whole month of October.