Want to be charmed, fascinated and intrigued? Or perhaps you are sick of the weather report getting it wrong and you are ready to take matters into your own hands. Either way, it is time to become a cloud spotter. Guest writer Beth Askham shows you how.
Warning: When cloud spotting never look directly at the sun.
What you need
- A sky
- A pillow, mat, a brilliant blue beach with the sounds of waves crashing or creaking crickets nearby (optional).
What to do
Rubberneck the sky. Look up, gaze across to the horizon, ogle above and beyond and see what is happening in the skies. If you have a camera, take photos of some fine cloud specimens to put in a summer cloud diary.
Clouds can be big and billowy, small and streaked, cheerfully white or grey and sinister. They are beautiful, mysterious and there is never a dull movement when out cloud spotting. Clouds can tell us what the air is doing and what kind of weather we can expect.
Despite their impressive forms and presence in the sky, clouds are just water droplets or ice crystals (or both) in the air — just like the steam from a kettle or your breath on a cold morning. A cloud will form when the water vapour in the air (that is usually invisible) cools down to a point where it becomes a water droplet or an ice crystal.
Clouds are mostly white because water droplets and ice crystals reflect all parts of the light spectrum equally.
Most clouds you see in the sky will have a name (useful for telling other cloud spotters what you have seen) and there are around 100 types of named clouds. Clouds are initially grouped into genera that are further broken down into species. Each species can be one of a number of varieties. When trying to find out what type of cloud you are seeing, look at its shape and its altitude — how high it is in the sky.
Summer sky challenge
Find each of these four genera of clouds in the sky this summer. We will give you clues about what time of day you might find them and in what kind of weather so it’s easy: just keep gazing upwards.
These are the easiest and friendliest cloud to spot. Cumulus are big billowing white puffy pillows of cloud that sit in the low in the sky and waft cheerfully along. They are formed when the air is warmed and rises upwards, so you are likely to see this cloud on a hot summer’s day. The rising hot air brings water vapour into the cooler heights of the sky, where it will cool into water droplets.
These clouds form over individual warm updrafts over the land and that’s why cumulus cloud are usually scattered randomly over the sky. A cumulus cloud will usually last for only around 10 minutes, after which it might disappear or change and turn into a more sinister rain cloud like the cumulonimbus.
Nimbus is the Latin word for rain or snow bearing. These clouds are at the heart of every wild and stormy rainfall and are huge billowing clouds, filling the low, middle and high altitudes of the lower atmosphere. They can form on hot days, when hot air full of water vapour rushes upwards. Raindrops and ice crystals inside these clouds fall downwards only to get pushed upwards by an updraft of air; they can be tossed around a cumulonimbus many times. These turbulent clouds can result in some fierce hail and rainstorms. Have a rain jacket handy when spotting for cumulonimbus.
These sit lower than all the other cloud types and they are the only cloud that you will ever be able to walk through. They can form and lurk in valleys and hollows in the mornings and can make a dreary grey sky-cover on a cold day.
These super-high clouds streak and curl across the higher altitudes of the lower atmosphere, around 5500 metres high. They are made from ice crystals and can cause a halo to form around the moon or the sun. These clouds are the fastest moving cloud even though they don’t seem to move at all from down here on the ground. They can sometimes mean that rain is on the way.
Happy cloud spotting!
|Very early morning stratus filling a valley|
|Pick the early morning cloud (don’t be fooled by distracting volcano steam)|
|Some high clouds on a hot summer’s day|
|Clouds come in all shapes and sizes|