Four deaths in four days on Mt Everest

There have been four deaths in four days on Mt Everest as the first climbing season for two years draws to a close. Two more are feared dead. The world's highest peak has been closed to climbers for two years following last year's earthquake and a major ice fall the previous year. Many climbing parties are trying to get to the summit in a limited weather window, leading to bottlenecks high on the summit, and claims again that inexperienced climbers are holding up others. Kathryn speaks with Norbu Tenzing of the American Himalayan Foundation.