Mystery Cloud Throws Istanbul Into Darkness

The city of İstanbul was caught on video being thrust into nighttime in the middle of the day as a terrifying black cloud engulfed the sky.

The video, which has been shared on social media and amassed hundreds of thousands of views, shows the Turkish capital turning pitch black as a roiling cloud descended across the city on Tuesday.

"A cloud 7 kilometers thick passed over İstanbul. In the meantime, the sun disappeared in 5 minutes, and the day turned into night. Some people commented on the apocalypse," the Turkish meteorological forum Hava Forum tweeted while sharing the video.

As the dark cloud descended across İstanbul, heavy rain began to fall across the city. The strange sight mystified other internet users.

"The end is near," one person commented on a different post sharing the video, while another Twitter user asked, "What the hell is it?"

Technology news site TechnoPixel suggested that this thick cloud may have been a particularly large and dark-colored cumulonimbus cloud. Also known as thunderclouds, they often have a very dark, low-hanging base, reaching as low as a few hundred feet above the ground, the United Kingdom's Meteorological (Met) Office explained. Cumulonimbus clouds are the only clouds that produce hail, thunder, and lightning, and also lead to heavy rain showers.

Particularly thick and moisture-leaden cumulonimbus clouds can appear extremely dark due to the cloud letting very little light through, which may explain the sudden darkness in Istanbul as the cloud blocked out the sun.

Cumulonimbus clouds usually form as a result of smaller clouds of water vapor in the lower troposphere being built upwards due to convective air currents. These clouds then grow taller and taller and contain more and more water, until they eventually have the same amount of energy as 10 Hiroshima-sized nuclear bombs, according to the Met Office. These clouds usually reach heights of around 40,000 feet but have occasionally been measured to be nearly 70,000 feet tall.

Cumulonimbus clouds will often rapidly dissipate in the aftermath of a rainstorm, as the dark clouds over Istanbul also reportedly did, with the sun re-emerging after only five minutes of darkness.

Other Twitter users in İstanbul shared images from within the city as the cloud rolled in, showing just how dark it suddenly became.

One user, @diversoce, posted a picture that showed a van having to turn on its headlights during the darkness. Another user, @profabuzerkomrc, uploaded a video of the heavy rain battering the city.

In the aftermath of the cloud, the weather proceeded to take a poetic turn, with a huge rainbow being plastered across the sky.

Another Twitter user, @zlem215857762 posted a picture of the rainbow, commenting "It was pretty good after that."

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