High winds and hard rain brought chaos across southern France, northern Spain and parts of Portugal on Thursday, forcing cancellations of flights, trains and ferries and disruption on roads.

French officials said a truck driver was killed when a tree smashed through his windscreen, while dozens were injured in weather-related incidents in Spain and a viaduct in Portugal partially collapsed because of flooding.

French forecasters said the storm, named Nils, was "unusually strong" and France's electricity distributor said it had mobilised around 3,000 as it battled to reconnect households to the grid.

"Enedis has restored service to 50 percent of the 900,000 customers who were without electricity," it wrote around 6:00 am (0500 GMT).

"Flooding complicates repairs because the fields are waterlogged and some roads are blocked," Enedis crisis director Herve Champenois said during a press briefing on Thursday.

Residents across the south of France were shocked at the storm's ferocity.

"I've never seen anything like it," Ingrid, a florist in the city of Perpignan, told AFP. "A tree almost fell on my car -- two seconds more and it would have."

"During the night, you could hear tiles lifting, rubbish bins rolling down the street -- it was crazy," said Eugenie Ferrier, 32, from the village of Roaillan near Bordeaux in the southwest.

Forecasters said the storm had moved eastwards away from French territory during Thursday, though some areas were still on alert for flooding.