Virga is rainfall that does not touch the ground. It is precipitation that falls from the base of a cloud, and then evaporates even before it reaches the ground. If you’re using radar to check for rainfall, you may be able to see that it’s raining. But in reality, you can neither see nor feel the rain. Virga clouds are one of the prettiest sights, but they are not as common as other types of clouds.
This type of precipitation is most common in desert and temperate climates. The reason for this is that there may be enough moisture in the upper levels of the atmosphere to form clouds and rain. However, as the rain falls to the surface, it encounters a much drier cloud. The dry air causes the moisture to evaporate before even hitting the ground. The evaporation process removes heat from the air around it, meaning that virga also happens to cool the air as they dry up.
Keep reading to learn more about Virga clouds, and don’t forget to share with your friends!
How Do Virga Cloud Form?
Most times, falling precipitation can only reach the ground if the air is saturated, or at least near saturated. However, this might not always be the case. If there is dry air below the clouds as at the time the precipitation starts to drop, the dry air evaporates the precipitation. This makes it a lot more difficult for the precipitation to reach the surface. This is what forms a virga cloud and gives the appearance of those super-stretchy, fluffy clouds.
What Does Virga Look Like?
Ever looked up to the sky and thought the clouds up there looked super fluffy, and stretchy, like cotton candy? That was probably a virga cloud. They appear like streaks or wisps under a cloud. They are also often called ‘jellyfish clouds‘ because just like jellyfish, they have a puffy-top exterior with streaky stingers drooping beneath. Asides from cotton candy and jellyfish, virga clouds often take the form of various other familiar objects in the sky. Occasionally, it gives the impression of a painted sky.
Different Types of Clouds Associated with Virga Clouds
One can find virga clouds in seven other types of clouds. These include; cirrocumulus clouds, altocumulus clouds, altostratus clouds, nimbostratus clouds, stratocumulus clouds, cumulus clouds, cumulonimbus clouds.
This means you can have a cirrocumulus virga cloud, an altocumulus virga, an altostratus virga, and so on.
Where Does Virga Happen?
Virga appears as streaks in the bottoms of clouds. You find them in areas of high temperature and low humidity, such as in the deserts. You can also find them at high altitudes. One can regularly spot virga clouds in the United States, the Middle East, the West of the Canadian Prairies, North America and, Australia, and North Africa.
Virga Clouds in Aviation?
Virga often occurs in higher altitudes, which means pilots are no stranger to these unique clouds. While inarguably pretty, virga clouds are sometimes hazardous in aviation. Occasionally virga clouds are harmless and transparent enough to fry through. But most of the time, to be safe, pilots typically avoid virga.
To understand the kind of threat a virga cloud poses in aviation, one must consider how these clouds form. Virga clouds form when falling rain or snow evaporates in the air before it reaches the ground. The reason for this evaporation is dry air underneath the clouds.
As falling precipitation evaporates to form virga, it cools the air around it, making it denser and heavier than the other air in the atmosphere.
Heavy air produces a downward draft as it accelerates down to earth. If an aircraft encounters a massive downward draft, it could cause the aircraft to lose altitude and this may end in fatalities. Furthermore, when the temperatures in the air get to freezing point, virga clouds may contain cold liquid water. One could encounter clear ice when trying to fly through them.
Pilots avoid virga if they are so solid that they become opaque or when in the middle of thunderstorms.
FAQs About Virga Clouds
Here are some frequently asked questions about virga clouds.
What Does Virga Mean?
Virga is a Latin word. It means “branch” or “twig.”
What Do Virga Clouds Indicate?
Virga clouds indicate that falling snow or rain encountered a region of dry air before it could get to the earth. It could also indicate an area of dense and heavy air.
What Are Some Characteristics of Virga?
Some major characteristics of virga are that it often looks like wisps about to fall off from the bottom of another cloud. They often form with other clouds and can be found in dry temperate regions.
What Are Virga Clouds Made of?
Virga clouds consist of strips of rain and precipitation. They make such a remarkable sight that many people who encounter them are tempted to take a photo.
Why Is Virga Bad?
Virga clouds, while picturesque, could be dangerous to aircraft. With virga clouds, there’s often a possibility for downbursts (also called microbursts). Downbursts are localized and strong wind columns that come up when cold air comes off the base of thunderstorms at a very high speed hit the ground then spread out in different directions.
A microburst could knock an aircraft off the sky, leading to fatalities. In 1975, downdrafts took down Eastern Airlines Flight 66. Since then, microbursts are taken a lot more seriously in the Aviation world.
Are Virga Clouds Rare?
The rareness of virga clouds depends on one’s location. It’s pretty common to see Virga clouds in the United States, Sweden, Australia, Middle-East, North Africa, and West Canadian Prairies.
What Weather Do Virga Clouds Bring?
Virga clouds are precipitation that attempted to fall to the ground and never made it down. They create a picturesque sky and could bring turbulence to aircraft that venture into them.
What Type of Cloud Produces Virga?
Seven different types of clouds are said to produce virga. They include cumulonimbus, cumulus, stratocumulus, nimbostratus, altostratus, altocumulus, and cirrocumulus clouds.
Which Condition Is Most Favorable for Virga Precipitation to Occur?
Atmospheric conditions of low humidity and high temperatures can cause virga clouds to form.