Hurricane-force winds, surging seas and driving rain lashed western Europe today, leaving at least 25 people dead and more than a million households without power.
Dubbed "Xynthia", the Atlantic storm crashed against the western coasts of France and Spain overnight, bringing with it a band of foul weather stretching from Portugal to the Netherlands.
Gusts of up to 150 kilometres per hour (93 mph) and eight metre (26 foot) waves battered the western coast of France, spreading floods inland and sending residents scurrying onto rooftops.
"We were warned, but I didn't think it could do this," said 62-year-old retiree Jean-Francois Dikczyk, who saw the sea surge several hundred metres (yards) inland and smash though the bay windows of his house in the town of Yves.
"My mother was nearly killed. She's 83 and disabled. She was sleeping on the ground floor, and her mattress was floating. My son and I managed to get her upstairs, but it was really catastrophic," he told AFP.
In all, 20 people were confirmed dead in France over the weekend, according to an AFP tally of official sources. Most of those lost were drowned in the flooded coastal towns of the Vendee and Charente-Maritime regions.
President Nicolas Sarkozy expressed his condolences for the families of the victims, praised the work of rescuers and ordered his interior minister to the worst hit area to coordinate the response.
Some boat owners ignored warnings and stayed onboard overnight in west coast marinas. "The boat was rolling so much it was like being on the ocean," said 60-year-old Robert Monne, who came ashore to find his car swept away.
Britain, already suffering localised flooding from a previous weather system, was braced for more weather misery if the trailing edge of the storm hits its south coast en route to Scandinavia.
In Spain, regional authorities said Sunday that two men aged 51 and 41 died when their car was hit by a falling tree. An 82-year-old woman was killed Saturday when a wall collapsed in the Galicia region.
In Germany, a man was killed and his wife injured when a tree fell on their car in the Black Forest as the storm raged northeast across the continent.
Portugal said Saturday that a 10-year-old boy was killed by a falling branch and flood waters continued to rise on Sunday.
The northern cities of Porto and Vila Nova de Gaia issued flood warnings as the Douro river threatened to break its banks.
There were no immediate reports of deaths in Belgium, but there was heavy rain and in the Charleroi district south of Brussels, emergency services were called out repeatedly to deal with fallen trees and power lines.
In France, fallen power lines caused blackouts for around a million homes across a 500 kilometre (310 mile) swathe of the country from the Brittany peninsula to the highlands of the Massif Central.
Air France said 100 flights out of 700 were cancelled from its hub at Paris Charles de Gaulle, where an AFP reporter saw sections of one terminal roof starting to come loose.
The storm brought chaos to transport networks across western Europe at the end of French schools' half-term break.
A major road crossing between France and Spain was closed to heavy goods vehicles, causing a 1,200-vehicle tailback on the French side.
Europe 1 radio reported wind speeds of 175 kilometres per hour at the tip of the Eiffel Tower in Paris, but "Xynthia" fell short of the record 200-kph levels of a deadly 1999 storm system.
"Xynthia" developed in the Atlantic off the Portuguese island of Madeira, still reeling from the flash floods sparked by heavy rains that wrecked the centre of the capital Funchal and killed 42 people a week ago.
The storm swept northeast into northwestern Spain late on Saturday afternoon, where wind gusts reached 147 kph and some 100,000 households were without electricity, regional authorities said.