The phenomenon is caused by light reflecting off tiny ice crystals inside the body of the cloud's water vapour.
'I only took a couple of shots as I was overwhelmed with feelings and wanted to see everything with my eyes and prolong the moment,' Mr Bartunov said.
'The light was coming from the sun, which was right under the clouds at the perfect angle to create the magical effect.'
When he witnessed the event he could hardly believe this eyes, so asked others nearby to confirm that it really was a rainbow cloud.
Mr Bartunov, who is a fellow at the Sternberg Astronomical Institute in Moscow, said: 'There was a group of elderly English women there.
'I told them to look at the clouds and they started to moan and sigh and started to photograph the clouds with their small photo cameras.'
via Rainbow cloud towers over Mount Everest | Mail Online.