October 8, 2025
3 minute read
Science behind record Everest snowstorm stranding hundreds of people
Experts explain that the snowstorm that trapped hundreds of tourists on Everest was truly “off the charts.”
Hundreds of hikers recently became trapped on Mount Everest, which is shown in a stock photo.
Davor Lovincic/Getty Images
A snowstorm that stranded hundreds of tourists on Everest's north side over the weekend made headlines due to its proximity to the famous peak. But less appreciated was the truly bizarre nature of the blizzard: the amount of snow that fell in 12 hours was 3.5 times more than anything previously measured on the mountain.
“This is off the charts in terms of the six-year record we have at weather stations on Everest,” says Tom Matthews, a climate scientist at King's College London who co-led a 2019 expedition to the highest weather station on Earth, Everest. [October] 4 a giant 23 feet high rolled down.”
About 900 tourists and guides were rescued in the days following the hurricane. according to the Associated Press. These men were trekking to and around a base camp on the north side of a mountain in Tibet during the Chinese National Day and Mid-Autumn Festival holiday break. In Nepal, the precipitation fell as rain, causing widespread flooding and landslides that killed at least 47 people. according to Al Jazeera.
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Last Friday and Saturday, a severe snowstorm dropped nearly three feet of snow in the Gama Valley in Tibet. according to reports. This occurred during what is typically a dry and mild period for the region. The rainy season in Tibet and Nepal lasts from May to mid-September. Most climbers try to conquer Everest in the spring, before the rainy season begins. The few climbers attempting the summit in October are tempted by fewer crowds and generally clear skies.
But it was not the climbers who suffered the most from the hurricane. The people trapped by the snow that fell on October 3 and 4 were tourists trying to view the mountain from its base in Tibet's Tingri county. The popular four to five day trek takes hikers from Old Tingri village to Everest's northern base camp called North Base Camp, which is located at an altitude of about 17,000 feet above sea level. Now people can also drive to North Base Camp, says Kent Moore, a professor of atmospheric physics at the University of Toronto in Mississauga who studies mountain meteorology. The route may have been busier than usual this past weekend due to the holidays.
“It’s easy to put yourself in a very dangerous situation right now,” Moore says. Twenty years ago, the event would have been a “nothing burger,” he adds, because there would have been no one in the area. But improving infrastructure in Tibet is attracting more and more people to Everest's remote north side. And because North Base Camp is easily accessible quickly, such hikers may not be as acclimatized to the high altitude as those going to the mountain's South Base Camp in Nepal, which requires about a two-week trek from Kathmandu.
“A snowstorm at sea level is not a big deal,” Moore says. “But when you're at 5,000 meters [16,440 feet]everything is just made more difficult.”
According to Nepal's Department of Hydrology and Meteorology (DHM), a low pressure system in the Bay of Bengal has intensified the monsoon, causing rainfall. Trekkers also reported wind and almost continuous lightning on the northern side of Everest. Meteorologists are still analyzing weather conditions, Matthews said. But two low pressure systems, one on each side of India, may have contributed to the event by sending high levels of water vapor from the Bay of Bengal into the Everest region. According to Moore, the problem may be exacerbated by the fact that the surface of the Bay of Bengal is currently two degrees Celsius warmer than its historical monthly average. Warmer water evaporates faster, creating more steam, which can then condense into snow.
Heavier precipitation expected to increase as the climate warms, Moore says. “This is simply because when the air is warmer, it can hold more water vapor,” he adds. “Water vapor is what leads to storms and precipitation.”
According to DHM Nepal, as of October 6, the monsoon was leaving the region.
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