'We thought it was a swarm of bees': Mysterious ring of smoke seen in the sky at Sentosa puzzles onlookers

SINGAPORE — A black smoke ring appeared in the sky over Sentosa on Sunday (Aug 6), leaving many at Tanjong Beach curious as to what the phenomenon was.

Marketing associate Nuruddin Selamat was one of them. The 31-year-old filmed the bizarre sight before posting it on video sharing platform TikTok.

In his video, playfully captioned "errmmm, should we start running?", a huge black smoke ring can be seen floating over palm trees on the beach. The clip has been viewed more than 17,000 times.

Nuruddin, who was having a drink and some snacks with his friends when he spotted the smoke ring, said: "Honestly, we were super confused, and we thought it was a swarm of bees.

"I was actually thinking if I should run, but I decided to take a video first because no one would believe me if I did not have evidence."

He added that the other beachgoers around him were also curious, and many followed it as it drifted.

Nuruddin said that the smokey oddity moved very slowly, and appeared to fade away after a few minutes.

Weather and climate scientist Koh Tieh Yong said that the smoke ring is not a weather phenomenon, but a vortex ring formed by a pulse of hot air shooting upward into a stable atmosphere.

Dr Koh said: "The vortex ring forms at the leading circular edge of the rising plume, and as it rises, the ring expands because the surrounding air is entrained into it."

He added: "We see the vortex ring, probably because smoke particles were injected into it from the moment the plume was shot and then were trapped inside since.

"The smoke concentration dilutes as the ring expands, and we see the ring grow faint. Eventually, the vortex ring dissipates when stronger winds at higher levels disrupt the organised rising motion of the plume."

Previously, similar smoke rings were spotted in Sentosa in 2022 and 2017, according to local media reports.

At the time, it was reported to most likely be smoke caused by fireworks testing for Sentosa's Wings of Time pyrotechnics show.

Mysterious smoke rings have also been seen in other countries in recent years. 

In March, one was spotted in Moscow, and Anton Gerashchenko, advisor to the minister of internal affairs of Ukraine, shared a clip of it on social media platform Twitter.

According to various media reports online, they could be vortex rings, which are formed when there is a sudden release of air or gas, or when smoke, dust or steam particles become trapped in a "vortex".

They can reportedly be created during the testing of explosives, chemical reactions, or when a volcano erupts.

The Straits Times has contacted Sentosa for more information.

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This article was first published in The Straits Times. Permission required for reproduction.