Fact Check

Video footage purportedly showing a rare ‘cloud avalanche’, sliding down a mountain top and crashing onto a lake on its toes, has gone viral on social media – LinkedIn this time.

The video shared on February 27 by Dr Subramanian Narayanan, a structural engineer at the Indian Institute of Technology Madras, has received over 5,000 responses, over 200 comments, and about 400 reposts.

“Unseen phenomenon (cloud avalanche) in Nepal, on the eastern wall of the Everest mountain range. Recorded by a group of mountaineers completely by chance,” he captioned the video on the social media platform. “A rainbow appears on the river, which increases the beauty and amazement.”

Narayanan has neither claimed ownership nor credited anyone for the video. This has resulted in uncertainty over the time of the occurrence and the uploader among those without prior knowledge of the film.

Many media outlets, including NDTV , News18, reported on the social media buzz surrounding the video clip.

Fact Check

NepalMinute has fact-checked the film’s content and can establish that the uploader, Narayanan, is not the original author and that his claim that the video was shot in the Mount Everest region is false.

This is not the first time the video has garnered such a large audience. The same video made the rounds on social media in the past, drawing just as many audiences. 

The video shared by @Nepali_keti gained immense popularity on Twitter after Twitter handle @ErikSolheim, with over 325k followers, shared a link to it. The video uploaded on March 15, 2021, has received more than 4,000 likes and around 1,200 retweets.

Our investigation led us to the Instagram account naren32, which appears to have published the video in January 2021.

The uploader writes: “Here comes full video of huge avalanche, had to spend overnight at Kapuche Lake in order to capture this moment and it eventually paid off.”

Unlike Narayanan’s assertion that the footage was taken from the eastern wall of the Mt Everest range, the video was captured in Kapuche Lake in Central Nepal, near the popular lake city Pokhara. For the record, Kapuche Lake is 300km from Mount Everest – as the crow flies.

The identity of the Instagram uploader cannot be established, though. Similarly, the video was published around the same time on the YouTube account ShresthaKiranZ. The video also provides some rare glimpses of the about-to-freeze azure blue Kapuche Lake and the glacier that feeds the lake. 

Kapuche Lake, the world’s lowest glacial lake, is a popular trekking destination.

Science behind the phenomenon

One of the comments on Narayanan’s video post offers a plausible explanation for the rare cloud avalanche. 

“Sudden change in surface temperature produces anabatic and catabatic situations but quite rare at that altitude,” noted Anand Kumar.

There may be some truth to his description of the event. 

According to the American Meteorological Society (AMS), anabatic winds occur when the winds are propelled upslope by daytime heat. When it cools, katabatic winds - the opposite of anabatic - flow down into the valley.

As a result of this cooling, the cloud inside becomes heavier and wetter as it condenses. This is clear in the video, in which the cameraman captures excellent moments while torn between fleeing and continuing to film. While he continued to shoot, the frigid wind brought thick, rainy clouds, which blew away their tents and drenched their bodies. A rainbow appears in the video as the sunlight is refracted (bent) by ice crystals and water.

Conclusion:  Although the video clip is garnering considerable attention on social media and is being promoted by news sources, it is not new. It was created in January 2021. The viral message also provides incorrect information about the location of the event.