當秋天變成北極：喜馬拉雅山的致命天氣震驚徒步旅行者

The Himalayas have long been a favorite destination for hikers and climbers, especially during the autumn season. Traditionally, this time of year is known for clear skies, calm winds, and breathtaking views of snow-covered peaks like Mount Everest. However, recent years have seen a shift in weather patterns, making autumn hiking more dangerous and unpredictable. Meteorologists have observed that the monsoon season, which typically ends before autumn, is now stretching into October. This change has led to more frequent episodes of extreme rainfall and hazardous conditions in the mountains.

Just last weekend, a sudden blizzard struck near the eastern face of Everest, trapping hundreds of tourists at an altitude of over 4,900 meters. Rescue operations managed to guide nearly 600 trekkers to safety by Tuesday, but one person died from hypothermia and altitude sickness. On the Nepal side, a South Korean mountaineer lost his life on Mera Peak, and communication with the outside world was delayed due to heavy rain and snow damaging phone lines. In Nepal, officials estimate that landslides and flash floods have killed around 60 people in the past week alone, which is highly unusual for October. Mountain guides like Riten Jangbu Sherpa have noticed that trekkers are increasingly caught in unexpected extreme weather, which has hurt the trekking and mountaineering business.

The monsoon season in northern India and Nepal used to last from June to mid-September, but now it often continues into October. Archana Shrestha, deputy director general at Nepal's department of hydrology and meteorology, says that most years in the past decade have seen monsoons lasting until the second week of October. The heavy rain and snow at the end of the season can cause blizzards and snowstorms, posing serious risks for hikers and climbers. Last weekend, the weather changed suddenly, with strong winds, dropping temperatures, and poor visibility. Roads that were previously safe became buried in snow, making travel impossible. On Cho Oyu, a mountain between China and Nepal, climbers had to retreat temporarily due to heavy snowfall. Some hikers near Everest battled hypothermia and spent most of their time clearing snow, unable to sleep for fear of being buried. Rescue teams used yaks and horses to help clear the snow and save those trapped.

Scientists believe that global warming is causing more moisture in the air, leading to torrential rains over short periods, often after long dry spells. This is different from the past, when monsoon showers were spread evenly over several months. Travel agents in places like Lhasa say that September and October used to be peak season with pleasant weather, but now extreme weather can appear suddenly, and temperatures drop quickly. Landslides and flash floods have killed dozens in Nepal recently. Weather experts say that the monsoon is becoming stronger because it is interacting more with another weather system called the westerly disturbance. This system brings cold air and rain from the Mediterranean region, and when it meets the warm, wet air of the monsoon, it can create more extreme weather.

The westerly disturbance used to be a winter phenomenon, arriving between December and March, but now it often comes earlier, during the monsoon and autumn. In early October, the westerly disturbance caused heavy rain and snow in eastern Nepal, where Everest is located. Scientists have found that warmer air is pushing clouds higher, allowing these weather systems to reach places like Tibet, which used to be dry. A recent study notes that the climate in the Qinghai-Tibet Plateau is becoming warmer and wetter, which could mean more unstable weather and frequent snowstorms.

Mountain guides say that the reliability of weather patterns has changed, and they can no longer assume that conditions will be the same from season to season. Flexible scheduling, real-time decision-making, and experienced leadership have become even more important for safe trekking and climbing in the Himalayas. The changing climate means that everyone who visits these mountains must be prepared for sudden changes and take extra precautions to stay safe.