Residents in Java, Indonesia became worried after witnessing several clouds that appeared circling at the top of Mount Merbabu, Mount Merapi, and Mount Lawu on Thursday.
Head of Data and Information Division of Semarang BMKG Climatology Station, Lis W Harmoko said that the clouds that appear at the top of the three mountains are lenticular clouds.
“Generally, the lenticular cloud is a cloud or cluster of clouds shaped like a plate or lens trapped in the lower atmospheric layer. It is trapped because the lenticularis cloud generally does not appear to move where it is formed, ”explained Harmoko.
He added that the appearance of lenticular clouds is a sign of the presence of mountain waves that are quite dangerous for flight routes.
The cloud also begins to form when wind currents flowing parallel to the earth’s surface meet the resistance of certain objects such as mountains.
“As a result of this resistance, air currents move vertically towards the top of the cloud,” he said.
If the air contains a lot of water vapor and is stable, then when it reaches the temperature of the dew point at the top of the mountain, the water vapor begins to condense into clouds following the contour of the mountain top.
“This is why the lenticular cloud does not seem to move because the cloud begins to form from the windward side at the top of the mountain and then disappears on the leeward side,” he added.
Source: Gelora, Tribun Bali