British holidaymakers were trapped after 50-tonne boulder blocked road . Falling rocks cut off ski resorts Val Thorens , Les Menuires and St Martin . The rock fell from a cliff at the end of an Alpine trail in southern France on Friday morning. Road was ruled too dangerous for large vehicles to use Friday morning .
British holidaymakers were trapped after 50-tonne boulder blocked road . Falling rocks cut off ski resorts Val Thorens , Les Menuires and St Martin . Thousands of skiers stranded in a 50-mile tailback in the French Alps . Road was ruled too dangerous for large vehicles to use Friday morning .