A 27-year-old British man has died after being swept away by an avalanche at the French ski resort of Val Thorens after unusually heavy storms across the Alps.

The victim, who has not been named, was reportedly at the side of a road at the lower side of the town when he was struck by a wall of snow that carried him 15 metres (50 ft) down the mountain on Thursday morning. He was taken to hospital in Grenoble with cardiorespiratory failure but died in the evening.

The incident took place as France’s Savoie and Haute Savoie departments and other Alpine regions were put under the highest alert for avalanches as heavy snow, rain and flooding caused chaos across the region.

“Two municipal police officers and a patrol of three gendarmes on foot, alerted by a witness, arrived at the scene as quickly as possible and managed to extract the victim, who was in cardiorespiratory arrest at the time,” the local police prefecture said.

The man was standing “at the side of the road … and was buried and swept some 15 metres below”, it said.

At least four people have been reported dead as a result of extreme weather in France, Italy and Switzerland that has cut off winter resorts, ​disrupted transport and left homes without electricity.

Easter skiers were advised on Friday to stick to designated runs and avoid going off piste. A high alert for avalanches has closed some resorts.

Snow is not unusual in the Alps in April, but the amount that has blanketed parts of of France, Switzerland and Italy took local people and officials by surprise.

Meteorologists recorded “exceptionally unusual” snowfall on Thursday, with 110cm (3.6 ft) in the French alpine resort of Tignes, where people were advised to stay indoors for several hours.

Other resorts recorded 80-90cm of snow.

It Italy, the bodies of a 64-year-old man and his 33-year-old son were found near Vicenza in the Veneto region, bringing the death toll in the country to three. The pair had volunteered to help with rescue efforts after heavy rains in the north of the country and were on their way when their car was swept away by the currents.

A 92-year-old man was found dead in his flooded home in the northern Piedmont region the previous day, the fire brigade said.

Dozens of roads were shut in all three countries as a result of fallen trees or the risk of avalanches, and heavy goods vehicles were banned from using the main Mont Blanc tunnel between France and Italy, leaving many stuck on the road linking the two countries.

Trains were also affected, and at one point more than 3,300 homes in France and 5,000 in Italy were left without power, according to authorities.

The mayor of Tignes, Serge Revial, said conditions were “intense and complicated”. He ordered people to stay indoors for their own safety on Thursday, but said the situation was slowly returning to normal on Friday.

In Italy, the air force’s weather service reported “intense and abundant” rain that turned to show above 1,800 metres.

In Switzerland, “exceptional” snowfall was reported in the south-western Valais canton. In the town of Sion, 36,000 people were advised to stay at home.