Why the Fall Climbing Season Became Lethal in the Himalayas
Bright heavens, gentle winds and a breathtaking view of Himalayan summits draped in white powder - that is the autumn setting that hikers on Mount Everest have come to love.
But this seems to be shifting.
Shifting Weather Patterns
Weather experts report the rainy season now stretches into fall, which is traditionally the mountain travel season.
Throughout this prolonged tail end of the rainy season, they have recorded at least one episode of extreme rainfall nearly every year for the previous ten years, with high-altitude weather becoming increasingly risky.
Latest Crisis on Everest
Recently, a shock snowstorm trapped hundreds of visitors near the eastern face of Mount Everest for days in freezing conditions at an elevation of more than 16,000ft.
Almost six hundred hikers were escorted to safety by the end of Tuesday, according to reports.
A single individual had died from hypothermia and altitude sickness, but the others were said to be in good condition.
Comparable Events Across the Region
The emergency was on the Tibetan slope but something similar had developed on the southern side, where a Korean mountaineer died on another Himalayan summit.
The world learned much later because communication lines were disrupted by torrential rains and heavy snowfall.
Authorities estimate that mudslides and flash floods in the country have claimed the lives of around sixty people over the past seven days.
"It is very atypical for autumn during which we anticipate the weather to stay calm," said Riten Jangbu Sherpa.
Business Consequences
Considering this is the preferred period, frequent storms like these have "affected our mountaineering and climbing industry," he added.
The monsoon season in the Indian subcontinent and Nepal typically continues from June to early autumn, but not anymore.
"Our data demonstrates that most of the years in the previous decade have had rainy seasons continuing until the middle of autumn, which is definitely a change," said a high-ranking weather expert.
Increasing Climate Extremes
More concerning is the heavy rain and snow the tail end of the period brings, like it occurred recently on 4 and 5 October.
High in the mountain range, such extreme weather translates to snowstorms and winter storms, which represents a significant danger for trekking, mountaineering and the travel industry.
Firsthand Experiences
That's what happened recently when the conditions shifted very abruptly - the winds began howling, mercury readings dropped sharply and sightlines decreased drastically.
The path that had comfortably brought the hikers to what was expected to be a breathtaking resting point was now covered in white accumulation and extremely difficult to navigate.
Still, one trekker, who had climbed these mountains more than a dozen occasions, reported he had "not once experienced weather like these" before.
Scientific Explanations
A primary big factor is the higher quantity of moisture in the atmosphere because of how the world has been heating up, researchers say.
That has contributed to torrential rains over a brief period of time, frequently after a prolonged period without rain – unlike in the previous era when monsoon showers were spread uniformly over the entire season.
A Turbocharged Monsoon
Climate experts report the rainy seasons in South Asia at times seem to have become more intense because they are more frequently interacting with an additional weather system, the westerly disturbance.
This is a low pressure system that originates in the Mediterranean area and travels east - it carries cold air that brings precipitation and sometimes snow to the subcontinent, neighboring countries and Nepal.
Global Change Effects
Scientists have also found that in a heating world, the growing interaction between westerly disturbances and seasonal rains is producing an additional atypical outcome.
The hotter atmosphere is forcing the clouds to greater altitudes, which indicates these atmospheric conditions are now able to cross the Himalayas and affect the Tibetan plateau and other areas that did not see as much precipitation before.
"The transformation is the reliability of patterns; we cannot presume that situations will behave the identical from season to season," commented an experienced mountain guide.
"That means adaptable planning, immediate decision-making, and experienced guidance [in the Himalayas] have become increasingly crucial."
