Why the Autumn Trekking Season Became Fatal in the Himalayas
Bright heavens, calm breezes and a breathtaking vista of Himalayan summits covered in white powder - that is the fall setting that trekkers on the world's highest peak have come to love.
But this appears to be transforming.
Changing Weather Patterns
Weather experts say the monsoon now stretches into autumn, which is historically the mountain travel season.
Throughout this prolonged tail end of monsoon, they have recorded at least one episode of heavy precipitation nearly every year for the past ten years, with high-altitude weather becoming increasingly risky.
Latest Crisis on Everest
Recently, a shock blizzard trapped several hundred of travelers near the eastern side of Everest for days in bitterly cold conditions at an elevation of more than 4,900m.
Nearly 600 hikers were guided to safety by the conclusion of that week, according to sources.
One person had succumbed from hypothermia and altitude sickness, but the remaining individuals were said to be in good health.
Similar Events Across the Region
The emergency was on the Tibetan side but a comparable situation had unfolded on the southern slope, where a Korean climber lost his life on Mera Peak.
The world learned much later because communication lines were hit by torrential rains and significant snow accumulation.
Authorities calculate that mudslides and sudden floods in the country have killed around 60 people over the previous seven days.
"This is very unusual for October when we anticipate the skies to remain calm," commented an experienced mountain guide.
Economic Consequences
Considering this is the favored season, frequent storms like these have "disrupted our trekking and mountaineering industry," he added.
The rainy period in northern India and Nepal usually continues from early summer to early autumn, but no longer.
"Research indicates that the majority of the annual cycles in the previous decade have had rainy seasons continuing until the middle of October, which is definitely a shift," explained a high-ranking weather expert.
Growing Weather Severity
More concerning is the intense precipitation and snowfall the tail end of the period brings, like it did recently on early October.
At elevation in the mountain range, such extreme conditions means blizzards and winter storms, which represents a huge danger for trekking, climbing and tourism.
Firsthand Experiences
That's what occurred recently when the conditions changed very abruptly - the air currents began roaring, mercury readings plummeted and visibility decreased significantly.
The path that had easily brought the hikers to what should have been a stunning resting point was now buried in white accumulation and extremely difficult to traverse.
Still, one trekker, who had climbed these mountains more than a dozen times, reported he had "not once encountered conditions like this" before.
Expert Explanations
One big driver is the increased quantity of humidity in the air because of how the world has been warming, scientists say.
This has contributed to heavy precipitation over a short span of time, frequently after a prolonged dry spell – in contrast to in the previous era when seasonal rains were distributed evenly over the entire season.
A Turbocharged Monsoon
Weather experts report the monsoons in South Asia at times seem to have become stronger because they are more frequently coming into contact with another weather system, the western weather pattern.
This is a low pressure system that originates in the Mediterranean area and moves east - it carries cold air that causes rains and occasionally snow to the subcontinent, neighboring countries and Nepal.
Climate Warming Effects
Scientists have also discovered that in a heating planet, the growing relationship between western weather systems and monsoons is producing an additional unusual outcome.
The warmer air is forcing the clouds higher, which means these atmospheric conditions are now able to cross the Himalayas and affect Tibet and other regions that did not see so much precipitation before.
"The transformation is the reliability of weather patterns; we cannot presume that conditions will occur the same from year to year," said an experienced expedition leader.
"This implies flexible planning, real-time decision-making, and experienced guidance [in the Himalayas] have become increasingly essential."
