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More than 1,000 people are dead after part of a glacier and mountainside in the Himalayas collapsed, unleashing a wall of ice, rock, mud and water through Nepal and Tibet. Thousands more remain missing.
Three months earlier, scientists had gathered with government officials in Kathmandu to talk about almost exactly this.
Experts met with government officials in May to discuss the growing danger from glaciers and glacial lakes along the shared Nepal-Tibet Himalayan border. They called for hazard mapping, monitoring, information-sharing, and early-warning systems.
By the time the mountain came down in late August, those warning systems still did not exist.
There is a terrible simplicity to what happened next.
The mountain moved.
This wasn’t an ordinary flood
Calling what happened a “flood” almost understates it.
Most floods begin with water. Rain falls. Rivers rise. Meteorologists watch the storm on radar; gauges record rainfall and river levels; models estimate where the water will go. Even flash floods generally have an identifiable meteorological cause developing before the water arrives.
This disaster began with the ground itself giving way.
On August 26, a huge mass near Langtang Lirung catastrophically failed. Early reports described a glacier collapse, but subsequent satellite analysis indicated that bedrock beneath the glacier failed with it.
An enormous section of mountain — rock, ice and everything attached to it — started falling.
The collapse released enough energy that seismic instruments initially registered what appeared to be an earthquake. The U.S. Geological Survey later concluded there had been no earthquake. The mountain falling apart had itself generated seismic energy equivalent to a magnitude 5.2 earthquake.
Gravity did the rest.
As the avalanche accelerated downhill, it collected soil, boulders, sediment, trees, ice and water. It entered streams and river channels and collected still more material. The narrow Himalayan valleys acted like a chute, concentrating all that mass and energy and directing it downstream.
The resulting debris flow traveled nearly 100 kilometers, destroying everything in its path.
One engineer assisting with the rescue effort estimated portions of it may have moved faster than 160 kilometers per hour.
That is the geographic reality of a disaster like this.
The sky doesn’t have to be raining.
The river doesn’t have to slowly rise.
The mountain can simply come down.
Scientists saw the danger
That doesn’t mean this was unforeseeable.
Scientists examining satellite imagery found changes on the glacier before the collapse. A rapid assessment by the scientific group HiRISK identified “pre-event indications” of instability.
Scientists had also spent years warning that the Hindu Kush Himalaya needed better monitoring and early-warning systems as its glaciers rapidly changed.
For people immediately below the collapse, there may have been little anyone could have done. When millions of tons of mountain begin moving above you, geography allows very little time for negotiation.
But geography also means the farther downstream you are, the more time exists between collapse and impact.
Scientists estimated some communities could have had ten minutes or more of warning. That doesn’t sound like much until the alternative is zero.
Ten minutes is enough to leave a riverbank.
Ten minutes is enough to run uphill.
Ten minutes is enough to stop traffic from entering a bridge or evacuate workers from a hydropower facility.
Ten minutes can be the difference between a disaster and a mass casualty event.
Instead, the avalanche tore through a landscape increasingly crowded with infrastructure. Roads, bridges, villages, hydropower plants and workers’ camps occupy the same narrow valleys through which gravity inevitably sends water, rock and ice.
Twelve hydropower facilities and a solar plant (together representing roughly 10% of Nepal’s operational electricity capacity) were shut down after the disaster.
That is another lesson here: climate disasters rarely remain politely confined to one category.
A glacier collapses.
It becomes a landslide.
The landslide becomes a debris flow.
The debris flow becomes a flood.
The flood becomes an energy crisis, an infrastructure disaster and a humanitarian catastrophe.
The mountains are changing
The underlying physics isn’t a mystery.
The Himalayas are warming. Glaciers are retreating. Permafrost (the frozen material that can help bind high mountain slopes together) is thawing.
Remove enough ice from fractures in a mountainside and you change its structural stability. Retreat a glacier and you remove enormous amounts of weight while exposing slopes that may not have been uncovered for centuries. Melt enough ice and water collects behind unstable natural dams, creating glacial lakes capable of bursting catastrophically.
Across the Hindu Kush Himalaya, glacier loss accelerated by 65% between the decades beginning in 2000 and 2010.
Even if humanity manages to keep warming below 2°C (a threshold we have already temporarily surpassed), researchers project the region’s glaciers could lose roughly 30–50% of their volume by the end of this century. Under current emissions trajectories, losses could approach 80%.
And this isn’t only Nepal’s problem.
The Hindu Kush Himalaya is sometimes called Earth’s “Third Pole” because of the enormous volume of ice stored there. Its snow and glaciers feed river systems that sustain communities across Asia.
What happens high in these mountains does not stay high in these mountains.
Neither does global warming.
We have spent decades talking about climate change as something coming toward us: a future crisis, measured in fractions of degrees and projections for 2050 or 2100. But the reality has always been the climate change is a disaster that is right here, right now, and does not have to only be measured in future possibilities.
Measure it in a glacier retreating up a valley.
Measure it in permafrost disappearing from the cracks holding a mountainside together.
Measure it in a river carrying boulders where, minutes earlier, people were working.
Measure it in the distance between a scientist’s warning and a government’s failure to act on it.
Because that may be the most damning part of what happened in Nepal and Tibet.
The mountain did not betray anyone.
The glacier did not ignore a warning.
Scientists identified the danger. They asked for monitoring. They asked for hazard maps. They asked for early-warning systems.
Then the climate kept warming.
The ice kept melting.
And we kept waiting.
Until heat and gravity answered for us.
Scientists are warning us where this is headed. My job is to make sure those warnings don't disappear into another report until after the next disaster. If that work matters to you, please support Mesoscale News with a paid subscription.