Four skiers have been killed and another injured in an avalanche in the French Alps, as the deadly Siberian weather system nicknamed "Beast from the East" continued to cause chaos across Europe. The group was on a ski touring expedition in an off-trail area near Entraunes, close to the Italian border in the southern Alps.The identities of the skiers were not immediately released. Prosecutor Jean-Michel Pretre of Nice said in remarks shown on French television that they were "seniors", all with experience in backcountry skiing. Meanwhile, the extraordinary weather system, which has now claimed more than 50 lives, continued to bring disruption to many countries across Europe. More than 20 people have died in Poland alone since the cold snap began, many believed to be rough sleepers.Some Polish cities have installed heaters in the streets in a bid to help the most vulnerable. Emergency shelters have been opened in many countries to help the homeless and citizens left stranded by disrupted transport services.