Watch part two
Filmmaker: Tanya Peterson
Norbu Sherpa clearly remembers the day the flood water obliterated all traces of his home from the rocky landscape high in the Himalayan mountain range.
Glaciers are melting due to global warming, causing lakes in the highest regions of the world to burst their banks.
Now Norbu has rebuilt his home on land high above the lake and this time his builders used thinner materials than before as there is less snowfall these days.
But from his new vantage point above the village, and in his role as a trekking guide for foreign tourists, Norbu can see trees dying from the drought caused by changing rainfall patterns.
Meanwhile newly-formed lakes pose increasingly greater threats to the Sherpa villagers living on the roof of the world.