BARAHBISE, Nepal, Looking at the swirling grey waters of the Bhote Koshi River, Ratna Kaji remembers when it turned into a "monster," leaving behind a trail of death and destruction.

"It came down roaring, washed away homes and people when they were sleeping," the 77-year-old said of the 1996 flood, caused by a massive landslide that blocked the river which eventually gushed out by breaking its mud wall.

"People had hardly any time to gather their belongings."