The Italian authorities have issued a nationwide warning, stressing the risk of avalanches in the Alps after heavy snowfalls and of downpours and gales in the south of the country caused by a deep depression centred on the Mediterranean.

Heavy snowfall in the French Alps and other southeastern regions left some 78,000 homes in the Rhone-Alpes region without power late Sunday as rainstorms also caused rivers to burst their banks, French authorities said. Earlier 145,000 households had been without power.

In the Isere, Ardeche and Drome departments in the southeast the national power company EDF said it was working to restore power lines, damaged by falling trees and branches brought down by the snow.

EDF said it had 1,000 staff in the field but that work was complicated by the poor weather conditions.

Snowfall is not uncommon in the region in April, but the more than 40 centimetres (15 inches) which have fallen since Saturday surprised traffic police and weathermen alike.

Road traffic was seriously disrupted in the Ain region in the Jura mountain range, with a major highway shut down entirely for a time, regional officials said.

Flood alerts were issued in the southeastern Rhone-Alpes region as well as in southern Auvergne and Burgundy, where more than 200 people had to be evacuated as several small rivers burst their banks, firefighters said.

Twelve Swiss holidaymakers were killed Sunday when a coach carrying 27 people skidded off a wet mountain road and plunged 200 metres (600 feet) into a ravine in southern Switzerland.

Four of those injured in the crash near the southern village of Orsieres were in a serious condition in intensive care, authorities in the southern canton of Valais said.

Some 200 rescuers, 15 ambulances and a helicopter were rushed to the site of the crash, north of the Great St Bernard pass that links Switzerland and Italy.

Authorities said the road was wet but not snowed up, while the valley was partly foggy at the time of the accident, the cause of which has yet to be determined.

After heavy falls of wet snow, which closed roads and railways, police in the Lausanne area in southern Switzerland banned people from walking in parks and woodland, fearing they would be injured by tree branches collapsing under the weight of the snow. Many cars were reported to have been damaged.

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