The Cloud Formation That Resembles a Fireball in the Sky

February 9, 2016 | Joanne Kennell

Fireball-shaped cloud
Photo credit: Rogerio Pacheco/Meteo Madeira

It has been described as the “Hand of God.”

No, this is not a giant ball of fire hurtling towards Earth — it is a cloud.  This incredible image was captured one morning at 8 a.m. last week by photographer and weather blogger, Rogerio Pacheco, over the Portuguese island of Madeira.

He described this cloud on his blog as “a fireball”, but commenters called it the “Hand of God” — it really does look like a fist.  Although what is occurring in the photo is not as dramatic as how it has been described, the simple science behind the incredible phenomenon is still incredibly fascinating.

This stunning photo is the result of atmospheric processes affecting ordinary clouds — cumulus and altostratus.

SEE ALSO: Why Do Nuclear Bombs Form Mushroom Shaped Clouds?

Cumulus, latin for heap, clouds are often found lower in the atmosphere, between 3,300 and 9,800 feet above the ground, and they often grow vertically in height.  They form when warm, moist air rises and eventually cools and condenses, forming the classic white, fluffy clouds in the sky.

Altostratus clouds are mid-level, gray/blue clouds composed of ice crystals and water droplets that usually cover the whole sky.  They are mid-level clouds found between 9,800 and 23,000 feet, and often form ahead of incoming storms with continuous rain or snow.

Luckily, Pacheco was in the right place at the right time because the way this cloud looks would not have lasted for a long time.

First of all, the red and orange colors are easy to explain — they are caused by the sunrise hitting the cloud at the right time.  “The cloud formation takes on a breathtaking appearance due to a phenomenon called light scattering,” meteorologist Quincy Vagell explained.  “At sunrise and sunset, light from the sun has to pass through a greater distance across earth's atmosphere, where the light is scattered. The result is that vibrant colors, such as reds and oranges, are more dominant.”

However, that doesn’t explain the dark spots seen at the top of the “fireball” and why it is so much lighter underneath.  This is a result of turbulent swirls of wind in the low- to mid-level of the atmosphere which mix two clouds from different altitudes.

"Though usually random, occasionally for a brief moment, clouds can take on an appearance of something more profound in this environment," Vagell said.  Mixing of different clouds at different altitudes happens all the time, we just don’t see it this strikingly because our eyes are not capable of distinguishing the similar shades of grey.

“I think the presence of a rising Sun has made [it] appear more striking than the clouds alone would appear,” said Emma Sharples from the UK's Met Office.  “We think they are probably cumulus clouds [cauliflower-shaped and fluffy], so pretty common, but enhanced by the light conditions.”

It has been a very interesting few months for cloud-spotters.  First, a magnificent video of undulus asperatus clouds was captured in Georgia, two rare cloud formations were spotted in the United Kingdom, and now this stunning cloud was photographed in Portugal.

I wonder what will be next.

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