A huge wave dragged a Polish woman to her death as she walked on a Spanish beach with a friend on Friday in a storm that also left a young French man missing.

As the powerful storm smashed into northeastern Catalonia, a big wave snatched away the 37-year-old Polish woman in the holiday resort of Lloret del Mar in the early hours, emergency services officials said.

"She was walking along the beach with a friend when she was surprised by a wave that dragged her in," said a police spokesman.

Her corpse was found five nautical miles down the coast near Blanes later in the morning, officials said, and she was identified by her clothes and jewellery.

The French man, described only as a young person, disappeared after going fishing in a rocky area of the coast of Roses, about 100 kilometres (60 miles) further north.

Only his fishing rod was recovered.

Emergency services were alerted by the French man's friend after he went fishing in a rocky area known as Carretera de Canyelles and failed to return, an emergency services spokesman said.

"This morning we found his fishing rod in a rocky area and began a search of the land and sea with helicopters and specialized vehicles," he said.

Catalonia's emergency services declared a state of alert on Friday because of forecasts for the weekend of heavy rain, rough seas with waves higher than 2.5 metres (eight feet) and strong winds.

The authorities warned people to avoid breakwaters, coastal paths and beaches affected by the waves.

Storms also beat down on the neighbouring northern Spanish region of Aragon, causing floods in the province of Zaragoza.

Spain has been punished by extreme weather in the past year.

After the driest winter in 70 years, forest fires scorched more than 184,000 hectares (454,000 acres) of land in the first nine months of 2012, the largest amount in a decade, according to government figures.