Clear skies, calm winds and majestic snowy peaks once defined autumn treks on Mount Everest. But that image is changing fast. The monsoon now extends deep into autumn, experts warn, bringing unpredictable weather and rising risks. For the past decade, meteorologists have observed at least one severe rainfall episode almost every year during this lengthened monsoon. And high in the mountains, such changes have turned deadly.
A blizzard traps hundreds near Everest
Last weekend, a sudden blizzard stranded hundreds of tourists near Everest’s eastern face. They spent days in freezing temperatures above 4,900 meters. By Tuesday, rescue teams had guided nearly 600 trekkers to safety, Chinese state media reported. One person died from hypothermia and altitude sickness, but others were said to be in good condition.
While this unfolded on the Tibetan side, tragedy struck in Nepal too. A South Korean climber died on Mera Peak. The world learned of it only later because torrential rains and heavy snow had cut off communications. Officials said landslides and flash floods killed around 60 people across Nepal over the past week.
“This is highly unusual for October when skies should stay clear,” said mountain guide Riten Jangbu Sherpa. He noted that trekkers are increasingly caught in unexpected storms. These erratic weather events have also “hampered our trekking and mountaineering business,” he added.
A longer, stronger monsoon
The monsoon in northern India and Nepal used to end by mid-September. That’s no longer true. “Most of the past decade has seen monsoons lasting until mid-October,” said Archana Shrestha from Nepal’s Department of Hydrology and Meteorology. She called this shift a clear sign of change.
More concerning is the heavy rain and snow that come at the season’s tail end. Early October brought “damaging precipitation in a short span of time,” Shrestha explained. In the Himalayas, that means blizzards and snowstorms, putting trekkers and climbers in grave danger.
Last weekend’s storm came without warning. Winds howled, temperatures plunged and visibility disappeared. The once scenic trail became impassable under thick snow.
On Cho Oyu, a peak straddling China and Nepal, climbers on the 8,201-meter mountain had to retreat temporarily. “They are back now after the heavy snowfall ended,” said expedition operator Mingma Sherpa, who led a six-member team.
Trekkers fight to survive the storm
For hikers near Everest’s eastern face, the ordeal was terrifying. Some said they fought hypothermia despite wearing proper gear. Others stayed awake through the night, afraid of being buried by snow. The snowfall was so intense that many spent hours shoveling just to stay safe.
A coordinated rescue effort, using yaks and horses to clear the trails, prevented further tragedy. One experienced trekker who has climbed these mountains over a dozen times said he had “never seen weather like this before.”
Scientists link the danger to higher moisture levels in the atmosphere caused by global warming. That extra moisture leads to intense downpours after long dry periods, unlike the steady rains of the past.
“The weather keeps changing every year now,” said Passang, a travel agent in Lhasa. “We can’t promise clients anything anymore. September and October used to bring perfect conditions, but now storms arrive suddenly and temperatures crash within hours.”
The turbocharged monsoon
Weather experts believe the South Asian monsoon is growing more powerful as it increasingly interacts with another system — the westerly disturbance. This low-pressure system forms in the Mediterranean and travels east, bringing cold air and moisture to northern India, Nepal and Pakistan.
When it collides with the warm, humid air of the monsoon, the result is extreme weather. “The westerly disturbance can effectively turbocharge the monsoon,” explained Akshay Deoras, a weather scientist at the University of Reading.
Traditionally, westerly disturbances arrived in winter, from December to March. Now, meteorologists say they are appearing much earlier, overlapping with the monsoon and autumn seasons.
The deluge in eastern Nepal and around Everest in early October came from this same clash. Nepal’s weather department confirmed that a westerly disturbance had fueled a low-pressure system from the Bay of Bengal, forcing clouds east instead of west.
A wetter, riskier future for the Himalayas
Scientists warn that the interaction between westerly systems and a warming monsoon is reshaping the region’s climate. Warmer air pushes clouds higher, allowing storms to cross the Himalayas into Tibet — areas once shielded from heavy rain.
A study in Nature published in June found that “a warming climate and stronger interaction between the westerly and Indian monsoon are turning the Qinghai-Tibet Plateau into a warmer, wetter region.”
The Tibetan Plateau has long been arid. Now, scientists fear that its shift toward warmth and moisture will bring unstable weather, snowstorms and blizzards.
“What’s changed is reliability,” said Logan Talbott, chief guide at Alpenglow Expeditions, which leads climbs on Everest’s Tibetan side. “We can’t assume the same conditions each season. Flexibility, real-time decisions and experienced leadership in the Himalayas have become more important than ever.”
