Tsunami of dirt: What caused Nepal's deadly glacial flood?

More than 150 people are dead and hundreds more are missing after an enormous wave of water, ice, mud and rock cascaded more than 170 kilometers (106 miles) down the Bhote Koshi River valley in Nepal. The valley is the main link between Kathmandu in Nepal and Lhasa in Tibet. At least 34 Australians are missing. There was little warning.