Avalanches killed at least three people in the French Alps on Tuesday, including a British and a Polish national, authorities said, bringing the toll this winter from such accidents to 28.

A group of five people were skiing off-piste in the mountains near the resort town of La Grave when the first avalanche struck, said the prosecutor's office in Gap, administrative capital of the Hautes-Alpes department in southeastern France.

Two of the skiers were killed, and another who was guiding the group was injured and taken to hospital.

The victims were both in their 30s: a Polish man and a Polish-born British man who was living in Switzerland, said prosecutor Marion Lozac'hmeur.

The two other skiers in the group, a German and an Australian, escaped unharmed.

The avalanche risk in the La Grave area, on La Meije mountain, was "high" on Tuesday -- four on a five-point scale -- because of a combination of fresh snow and wind, according to the French weather service.

Adding to what has been a deadly avalanche season in the French Alps, another avalanche later swept away several hikers in Valloire, in the neighbouring department of Savoie, Mayor Jean-Pierre Rougeaux told AFP.

Prosecutors said the avalanche had killed one person and left two others in critical condition.

All were French nationals.

The avalanche risk in the area at the time was at the maximum of five.

Prosecutors have opened investigations to determine the causes of death and injury in both avalanches.

The latest deaths bring to 28 the number of people killed in avalanches in France since the start of the season, with the majority occurring since January, including six in one weekend.

An avalanche killed three off-piste skiers, including two British nationals, in the French Alps on Friday last week, a day after several ski resorts closed due to the risk of snowslides.