Why the Autumn Trekking Period Became Deadly in the Himalayan Mountains
Clear skies, gentle breezes and a panoramic vista of Himalayan peaks draped in snow - that is the autumn experience that hikers on the world's highest peak have come to love.
However this appears to be transforming.
Changing Climate Conditions
Weather experts say the monsoon now stretches into fall, which is historically the mountain travel period.
During this prolonged tail end of the rainy season, they have documented at least one occurrence of heavy rainfall nearly every year for the previous decade, with high-altitude weather becoming increasingly risky.
Latest Emergency on Everest
Recently, a unexpected snowstorm trapped hundreds of tourists near the east-facing face of Mount Everest for days in bitterly cold temperatures at an altitude of more than 4,900m.
Nearly six hundred hikers were escorted to security by the conclusion of that week, according to sources.
One individual had died from hypothermia and mountain sickness, but the remaining individuals were reportedly in stable health.
Similar Events Across the Region
This was on the Tibetan slope but something similar had unfolded on the Nepal side, where a Korean mountaineer lost his life on Mera Peak.
The world learned after some delay because communication lines were hit by heavy downpours and heavy snowfall.
Officials calculate that mudslides and sudden floods in the region have killed approximately sixty individuals over the past week.
"This is highly unusual for autumn during which we expect the weather to stay clear," said an experienced mountain guide.
Economic Impact
Considering this is the favored period, frequent extreme weather events like this have "hampered our mountaineering and climbing business," he continued.
The monsoon season in the Indian subcontinent and the Himalayan nation typically continues from June to mid-September, but not anymore.
"Research indicates that the majority of the years in the past decade have had monsoons lasting until the middle of October, which is definitely a change," explained a senior meteorology official.
Growing Climate Severity
Even more worrying is the heavy precipitation and snowfall the concluding phase of the season produces, like it occurred this time on 4 and 5 October.
High in the mountain range, such extreme conditions means blizzards and snowstorms, which represents a significant risk for hiking, climbing and the travel industry.
Personal Accounts
Exactly what happened recently when the conditions shifted quite abruptly - the air currents began howling, temperatures dropped sharply and sightlines dropped drastically.
The path that had easily brought the trekkers to what should have been a breathtaking pitstop was now covered in snow and impossible to navigate.
Still, one hiker, who had hiked these mountains more than a twelve times, said he had "not once encountered conditions like these" before.
Scientific Analysis
One big driver is the higher quantity of moisture in the atmosphere because of how the planet has been heating up, researchers say.
This has contributed to heavy precipitation over a short span of duration, frequently after a prolonged dry spell – unlike in the previous era when seasonal rains were distributed evenly over four months.
A Turbocharged Monsoon
Weather specialists report the monsoons in South Asia at times appear to have become more intense because they are increasingly coming into contact with another weather system, the western weather pattern.
The phenomenon is a atmospheric depression that forms in the Mediterranean region and travels eastward - it transports cold air that brings precipitation and occasionally snow to the subcontinent, Pakistan and Nepal.
Climate Change Effects
Scientists have additionally discovered that in a warming world, the growing interaction between westerly disturbances and monsoons is producing an additional unusual result.
The hotter air is forcing the clouds higher, which indicates these weather systems are now capable to cross the mountain barrier and reach Tibet and additional regions that previously experienced less so much rain before.
"What's changed is the predictability of patterns; we cannot presume that situations will behave the same from season to season," commented an seasoned expedition leader.
"That means flexible planning, immediate decision-making, and experienced leadership [in the Himalayas] have become increasingly important."