Scientists have figured out why Everest makes strange noises at night
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As soon as the sun sets behind the Himalayas and the temperature drops, eerie sounds are heard in the depths of the glaciers around Everest.
Researchers led by glaciologist Yevgeny Podolsky have discovered that a chorus of rumbling and cracking sounds on high-mountain glaciers is the result of extreme temperature swings after dark, causing the ice to crack.
The team pinpointed the cause of the sounds in 2018 by spending more than a week trekking through the Nepalese Himalayas to test for seismic activity in the local Trakarding-Trambau glacier system.
Dr. Podolsky, along with other scientists, spent three weeks on a glacier near Mount Everest, not sure what caused the booming night sounds, but confirmed that they were associated with extreme cold.
This study was one of the first to show such a large amount of seismic activity due to thermal ice breaking, based on a vast body of research on the behavior of glaciers as the effects of climate change constantly warm the planet.
Dave Hahn, expedition leader who summited 15 summits of Everest, said he heard strange noises at night when he and other climbers were resting.
When Dr. Podolsky and his team traveled to the Nepalese Himalayas to test the seismic activity of the Trucking-Trambau glaciers, they landed on one of them about three miles above sea level, in full view of Mount Everest, which is about 8800 meters high.
Dr. Podolsky, Center for Arctic Studies, Hokkaido University, Japan: “It was an amazing experience because it’s such an interesting area.”
During the day, Dr. Podolsky and his team could work comfortably in T-shirts. But as darkness fell, the temperature dropped to about -15 degrees Celsius, or 5 degrees Fahrenheit.
As darkness fell, the scientists heard a “loud rumble,” adding, “We have noticed that our glacier is cracking or cracking at night.”
The researchers placed sensors on the ice to measure vibrations deep within the glacier – the same technology used to measure the magnitude of earthquakes.
The scientists collected seismic vibration data and compared it with data on temperature and wind, which helped to establish a strong link between temperature changes and nighttime noise.
Dr. Podolsky and his fellow researchers wrote in Geophysical Research Letters: “Local ice is very sensitive to such high rates of change.”
The study could help more groups of glaciologists and climate experts understand the behavior of glaciers in remote areas that contain some of the largest ice reserves on Earth.
The ice sheet in the Himalayas is melting at a devastating rate, putting millions of people and the economies of South Asia at risk. Massive ice sheets in the region have shrunk 10 times faster in the last four decades than in the previous seven centuries.
A 2021 study published in the journal Scientific Reports found that Himalayan glaciers have lost about 40 percent of their area over the past few hundred years, or about 390 to 586 cubic kilometers of ice — enough to raise global sea levels by 0.92- 1.38 mm.
Christina DENISYUK.
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