YOUR WEEKLY DOSE OF WOWZERS AND WONDER FROM THE NATURAL WORLD
There’s a good chance that if you look out your window, you’ll be able to see this week’s topic floating by.
We’re talking about something that can be fun to watch or sometimes scary, depending on the situation.
This week, we’re exploring the billowing world of clouds!
The term cloud describes water droplets, ice crystals, and other particles suspended in the Earth’s upper atmosphere where we can see them.
They’re studied by scientists called nephrologists.
According to the UK’s Met Office, NASA’s Earth Observatory estimates that at any given time roughly 67% of the planet is covered in clouds.
They form when warm, moist air rises and later cools higher in the atmosphere.
This vapor condenses on microscopic dust particles, much like the moisture that collects on the outside of a cold glass of water on a hot day.
Depending on the temperature, this process results in tiny water droplets or ice crystals.
Clouds appear white because they reflect and scatter sunlight as it passes through them.
If the clouds get thick enough or there are lots of separate clouds around, they can block the light and create a darker, grey appearance.
Clouds can hold millions of litres of water, transporting the moisture across vast distances, before depositing it elsewhere in the form of rain, snow, hail, or sleet.
This process of water evaporating, condensing, and falling again is known as the water cycle.
All that moisture means clouds can weigh hundreds of thousands of kilograms!
Despite this weight, however, they can really move!
When caught in the jet stream, a cloud can move at more than 160 kilometers (100 miles) per hour! Even big, moisture-rich thunderstorms can move at speeds of 48 kilometers (roughly 30 miles) per hour!
Clouds are categorized based on how and where in the atmosphere they form.
There are three main cloud types:
Cirrus clouds are the thin, wispy clouds that appear really high in the sky, often between 6,500 to 20,000 feet. Because of the high winds, they’re often displayed in long ribbon or streamer shapes.
Stratus clouds are flat like a bedsheet, and are often found at around 6,000 feet. They can sometimes create foggy conditions.
Cumulous clouds are clouds found at an altitude of less than 2,000 feet. These are the puffy, cotton-like clouds you probably find different shapes in if you like to cloud watch. They grow vertically, often creating huge cloud columns.
There are also variations on each of these cloud types, including altocumulus, altostratus, cirrocumulus, cirrostratus, cumulonimbus, nimbostratus, and stratocumulus.
Cumulonimbus clouds can be found at a wide range of heights between 1,500 feet and 40,000 feet.
These are most often responsible for severe weather such as thunderstorms, tornados, lightning, and hail.
Sometimes, the rain will fall from these clouds but not reach the ground. This creates a hazy column that hangs from the bottom of clouds call virga.
But if the bottom of your storm clouds look like they’re covered in bumpy pouches or kind of like a cow’s udder, look out!
These are rare Mammatus clouds and they typically mean that severe weather, such as thunderstorms, tornados, or hail is on the way.
Learning about the clouds around you is an excellent way to understand what to expect from the weather, and is a fun past-time that requires no scientific equipment.
Clouds are something everyone on the planet can experience and we think that makes them particularly Wowzerful!
Other planets in our Solar System have clouds too! Venus has thick clouds of sulfur dioxide. Jupiter and Saturn have clouds of ammonia.
The heat and moisture from the exhaust of airplanes can mix with cold air to create man-made clouds called contrails which streak across the sky.
A single cumulus cloud can weigh nearly 500,000 kilograms (1.1 million pounds),but its surface area and warm air currents allow it to float in the air!
Sometimes the heat generated by big wildfires or volcanic eruptions can create clouds. These are known as pyrocumulus clouds or pyrocumulonimbus clouds and can produce spectacular lightning storms.
See how clouds form and how they’re classified in this informative animated guide from Beautiful Science.