BARAHBISE, Nepal (Reuters) - 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."
Within minutes, the flood washed away 54 people in this beautiful but rugged area, destroying 22 houses and a section of the Kodari road, a major artery connecting the Nepali capital of Kathmandu to Tibet. The road is also used by climbers to get to the northern side of Mount Everest.
That wasn't the first time that Kaji saw tragedy strike the area around Barahbise, a trading town of more than 6,000 people some 100 km (62 miles) northeast of Kathmandu -- and climate scientists fear it won't be the last.
Global warming, which is hitting Nepal particularly hard, is causing glaciers to melt, raising the specter of another disaster like the one in 1981. Then, the flow from a glacial lake in Tibet set off a flood that killed at least five people in Nepal and caused widespread destruction.
There are more than 3,200 glaciers in Nepal, and 14 of them are at risk of bursting the dams which control the melting water that flows from them, officials say.
"The melting of glaciers that forms lakes can only be attributed to climate change," said Arun Bhakta Shrestha, climate change specialist at the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD), which studies climate change in the Hindu Kush Himalayas.
"There is no reason other than this for the change in the glaciers."
According to ICIMOD, which oversees a vast swathe of rugged land from Pakistan to Myanmar, the earth's temperature has increased by an average of 0.74 degrees Celsius over the past 100 years.
But warming across the Himalayas has been greater than the global average, with dire consequences.
Government officials said the average temperature in Nepal was rising by 0.06 degrees Celsius annually, due in part to its location between India and China, two of the world's heaviest polluters.
Over the past three decades, Bhutan's glaciers have shrunk by 22 percent and Nepal's by 21 percent, according to three studies recently released by ICIMOD.
They add that the melting glaciers will have an adverse impact on biodiversity, hydropower, industries and agriculture, flooding hydroelectric plants and inundating fields.
The region is also becoming ever more dangerous to live in.
The area in Tibet where the Bhote Koshi River originates has several glacial lakes, Shrestha said. Nine of them are at risk of bursting their dams.
"This could happen any time and the downstream areas are at very high risk of another flood," said the bespectacled scientist.
A flood of the same scale as 1981 would now take a greater toll in new settlements and destroy more infrastructure, including roads, he warned.
Even minor damage to the Kodari road could disrupt trade with Tibet, which totaled $131 million in the period from mid-July 2010 to mid-July 2011, up from $94 million the year before.
More widespread damage could deal a severe blow to tourism, a key pillar of the impoverished local economy, which relies on that and aid for survival.
In a worst-case scenario, global warming could eventually threaten more than 1.3 billion people living in the basins of 10 major Asian rivers that originate from the Himalayan glaciers, including the mighty Indus.
On the frontline are villages such as Barahbise.
"During the entire rainy season we don't sleep well, always fearing that another flood could hit our village," said Bharat Thapa, who grows rice and corn on a small plot of land next to the river bank where he lives.
"I know it is risky to live here, but I have no alternative because the river bed is fertile and I can have a good harvest."
Experts say mountainous Nepal is responsible for only 0.025 percent of global greenhouse gas emissions, among the lowest in the world.
The irony Nepal's dilemma is not lost on Thapa.
"We are not responsible for the climate change. Why are we made to suffer then?."
Reporting by Gopal Sharma, editing by Paul Casciato