Why the Autumn Trekking Season Became Deadly in the Himalayas
Bright heavens, calm breezes and a breathtaking vista of majestic peaks covered in white powder - that is the autumn setting that hikers on the world's highest peak have come to love.
However this appears to be transforming.
Shifting Weather Patterns
Climate scientists say the rainy season now stretches into fall, which is traditionally the mountain travel season.
Throughout this prolonged conclusion of the rainy season, they have observed at least one occurrence of heavy precipitation almost every year for the previous ten years, with high-altitude weather becoming more dangerous.
Latest Emergency on Everest
Recently, a sudden blizzard stranded several hundred of travelers near the east-facing side of Mount Everest for multiple days in freezing conditions at an altitude of more than 16,000ft.
Nearly six hundred hikers were guided to safety by the end of that week, according to reports.
A single individual had died from hypothermia and mountain sickness, but the remaining individuals were reportedly in stable condition.
Similar Incidents Across the Region
The emergency was on the Tibetan slope but a comparable situation had unfolded on the Nepal slope, where a Korean climber lost his life on Mera Peak.
The international community found out much later because communication lines were affected by heavy downpours and heavy snowfall.
Authorities estimate that landslides and sudden floods in the country have killed around 60 individuals over the past week.
"It is highly atypical for October during which we anticipate the skies to stay calm," said Riten Jangbu Sherpa.
Economic Impact
Considering autumn represents the preferred period, regular storms like these have "disrupted our mountaineering and mountaineering industry," he added.
The rainy period in northern India and the Himalayan nation usually lasts from June to mid-September, but not anymore.
"Research shows that the majority of the annual cycles in the past decade have had rainy seasons lasting until the middle of October, which is definitely a change," explained a high-ranking weather expert.
Increasing Weather Severity
More concerning is the heavy rain and snowfall the tail end of the period produces, like it occurred recently on 4 and 5 October.
At elevation in the Himalayas, such extreme conditions means blizzards and snowstorms, which represents a significant danger for hiking, mountaineering and the travel industry.
Personal Accounts
Exactly what occurred recently when the weather changed quite abruptly - the air currents began howling, mercury readings dropped sharply and sightlines decreased drastically.
The trail that had easily brought the trekkers to what should have been a stunning pitstop was now covered in snow and impossible to traverse.
Nevertheless, one hiker, who had climbed these mountains more than a dozen occasions, said he had "never experienced weather like this" before.
Scientific Explanations
One major driver is the increased amount of humidity in the atmosphere because of how the world has been heating up, researchers say.
This has led to heavy precipitation over a brief period of time, often after a extended period without rain – in contrast to in the previous era when seasonal rains were spread evenly over the entire season.
A Turbocharged Monsoon
Climate experts report the monsoons in South Asia at times seem to have become stronger because they are more frequently interacting with another atmospheric phenomenon, the western weather pattern.
This is a low pressure system that forms in the Mediterranean area and moves east - it transports chillier temperatures that brings precipitation and sometimes snow to northern India, Pakistan and the Himalayan region.
Global Change Effects
Scientists have also discovered that in a heating planet, the growing relationship between western weather systems and seasonal rains is producing another unusual result.
The warmer air is forcing the clouds to greater altitudes, which means these atmospheric conditions are now able to cross the mountain barrier and reach the Tibetan plateau and other regions that did not see so much precipitation in the past.
"The transformation is the reliability of weather patterns; we can't assume that conditions will behave the identical from year to year," said an experienced mountain guide.
"That means flexible planning, immediate choices, and experienced guidance [in the Himalayas] have become increasingly important."