Some glaciers near Mount Everest are melting year-round

Today’s Image of the Day from NASA Earth Observatory features glaciers in the Himalayas that lack the fresh coat of snow that is typically observed in January each year. The false-color image captures the high glacier passes of Nanpa La and Nup La, located around 30 miles northwest of Mount Everest, on January 17, 2021. 

From October 2020 to January 2021, the average snow line on these glaciers increased by around 330 feet. According to NASA, this phenomenon is tied to unusual winter melting in recent months. 

“A substantial area of the glaciers are now probably experiencing melting year round,” said Mauri Pelto, a glaciologist at Nichols College. “In years past, most melting stopped during winter and the snow line didn’t move, but that’s not really the case now.”

The experts report thay the melting period in the region around Mount Everest has been extended by four months as a result of abnormally warm temperatures.

“We have been basically seeing spring and summer-like conditions in the middle of winter,” said Tom Matthews, a climate scientist at Loughborough University who helps manage weather stations at Mount Everest. 

Matthews explained that these melting events are associated with pulses of warm air carried in by prevailing winds from the west.

The researchers have also observed less snow accumulating during the summer monsoon in recent years, which is when the region receives about  75 percent of its annual snowfall.

By contrast, the team found that there was an increase of rain and melting during the summer monsoon in 2019 and 2020 that reduced the amount of snowfall near Everest. Furthermore, warmer temperatures are melting snow that was accumulated before the monsoon seasons. 

“I have seen snow-free situations last into January before, but usually the snow line isn’t this high to start with,” said Pelto.

“I don’t think the ablation (melting) season is near ending. Until you get new snowfall, you will continue to experience melting and sublimation. It is evident that the ablation season length and ablation area on these high elevation glaciers is expanding.”

The image was acquired by the Operational Land Imager (OLI) on Landsat 8.

Image Credit: NASA Earth Observatory 

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By Chrissy Sexton, Earth.com Staff Writer