A Dead Glacier Is a Loss. A Dying One Is a Threat. Melting ice from the Himalayas is creating thousands of unstable lakes, a growing menace to towns and cities below.

The ice of the Himalayas is wasting away. Glacier-draped slopes are going bare. The ground atop the mountain range, which sprawls across five Asian countries, is slumping and sliding as the ice beneath it — ice that held the land together — disappears. Meltwater is puddling in the valleys below, forming deep lakes.

As the planet warms, so much ice has been erased from around Mount Everest that the elevation at base camp in Nepal, which sits on a melting glacier, has dropped more than 220 feet since the 1980s.

But this loss is not unfolding gradually.

Often it begins slowly, imperceptibly — and then it happens all at once, with catastrophic consequences for the people below. That was how it went on a warm August day last year.

Thame, a secluded village of 370 people, sits in a valley in the Everest region. Glacial melt had been pooling rapidly in a high spot above the village for more than a decade. The resulting lake was so remote that nobody had given it a name. That summer day, rocks from the surrounding mountains fell hundreds of feet and landed in this lake, displacing an enormous amount of water. The water rushed half a mile down the valley and into another lake, heaving up more water. Flood path captured by satellite on Sept. 18, 2024 Soon, 100 million gallons were coursing downhill, toward the village. People in Thame heard a crescendoing roar.

By the time the water raged through, it was as if a swath of the village had never existed. The medical clinic, gone. The school, destroyed. Two dozen homes and trekking lodges, plus fields and fields of potatoes — wiped out.

As the flood charged through Thame, the headmaster of the village school fled to higher ground and captured this video. Om Prasad Bhattarai

Months later, a scientist named Scott Watson was walking the flood’s path in reverse, up the steep valleys, up past mud-encrus