France - President Nicolas Sarkozy promised on Monday to investigate how sea levees broke during heavy storms at the weekend, unleashing floods that killed at least 51 people.

Sarkozy visited the coastal town of L'Aiguillon-sur-Mer, the hardest hit area of France where 25 bodies have been recovered after a dike collapsed, causing sudden overnight flooding that trapped many victims in their beds.

We have to find out how families in France in the 21st century can be surprised in their sleep and drowned in their own houses, Sarkozy said afterwards at a meeting with local authorities in the western city of La Rochelle.

We have to shed light as urgently as possible on this unacceptable and incomprehensible drama, he said.

The government has declared a natural disaster, which will enable victims to claim compensation and free up insurance flooding claims and it has also announced it will seek European Union aid for the region.

Sarkozy, who pledged 3 million euros ($4 million) to help victims, said there would be a detailed examination of the causes of the disaster, a plan to strengthen sea levees and emergency help for farmers.

SWIM TO SAFETY

He said he wanted to avoid hasty conclusions but he added it was important to draw lessons from the disaster which has already prompted questions about building rules on the coast and the safety of sea levees.
It shouldn't stop us analysing the levees, their solidity, their adaptability to current conditions and there is urban planning as well. You can't just build anywhere, he said.

Heavy rain combined with strong gusts of winds and high tides destroyed several Atlantic coastal sea walls along the western regions of Vendee and Charente Maritime at the weekend.

Many people woke to find their houses already flooded and several people told how they had to swim to safety as water poured in through the windows of their houses.

Victims driven out of their flooded homes were put up in temporary shelters and numerous injured were flown to nearby hospitals. Around 172,200 households were without electricity at 3.00 p.m. (1400 GMT), according to power group EDF.

Initial reports suggested the damage was caused by an unusual combination of extremely high winds of up to 160 km (99 miles) per hour, strong tides and an atmospheric depression which exacerbated the sudden rise in water levels.

(Reporting by Thierry Leveque, Claude Canellas, Guillaume Frouin, James Mackenzie; editing by Ralph Boulton)