(image credit: by Aleksandar Pasaric )
Not all rain makes it to the ground. In arid regions, a mysterious weather phenomenon known as “virga” causes rain to vanish midair, creating stunning visuals and stirring curiosity about the science behind it.
What Is Virga?
Virga (pronounced VUR-guh) is a type of precipitation that begins its descent from clouds like regular rain—but evaporates before it reaches the ground. This meteorological illusion occurs when falling raindrops pass through a layer of dry air, which absorbs the moisture before it ever touches the surface.
Where Can You See It?
Virga is most commonly observed in desert or semi-arid climates, such as:
The American Southwest (Arizona, New Mexico)
Parts of Australia
Central Asia and the Middle East
From the ground, it appears as wispy, streak-like trails hanging beneath clouds—almost like ghostly curtains of rain that never arrive.
Why Does It Happen?
The key ingredient is dry air below the cloud base. As rain falls into this layer, it encounters warmer, less humid conditions. The raindrops evaporate during their fall, a process known as sublimation (when solid or liquid turns directly into vapor). The lower the humidity, the faster this happens.
In some cases, snowflakes undergo the same fate, sublimating before they hit the ground—creating “snow virga.”
Is Virga Just for Show?
While virga is visually stunning, it also has practical implications in weather science:
It can cool down the air beneath the cloud due to evaporation.
It sometimes triggers microbursts—intense downdrafts that can be dangerous for aviation.
It’s a helpful indicator of atmospheric dryness, which can inform forecasts about fire risk or drought conditions.
A Photographer’s Dream
The sight of virga is not only a meteorological wonder—it’s also a favorite subject for weather photographers. The rain-like streaks against dramatic skies offer surreal visuals, especially during sunset or near mountains.
