Nepali officials say ice fall may have triggered massive volume of water

Navin Singh KhadkaEnvironment correspondent, BBC World Service Whenever there is a flood like this in the Himalayas, one question that comes up spontaneously is: what caused it? And the problem often is there is no definitive answer instantly. The difficult terrain of the Himalayas including in Tibet, where some say the flood originated, and where there is hardly any human presence, is the main reason. Experts therefore try to analyse satellite images, but monsoon clouds have not been so helpful