![Spectators observing the solar eclipse in Hopkinsville, Kentucky, on August 21, 2017.](https://dynaimage.cdn.cnn.com/cnn/digital-images/org/b0a5c779-83a2-42c9-bd50-2d6a57ba6f68.jpg)
As it approaches midday, the sun takes its high throne in an azure blue sky, sprinkled with fluffy, cauliflower-form clouds. Suddenly, the clouds that were filling the horizon start to fade into nothingness. Soon after, sunshine is swallowed up by darkness as the sun vanishes from sight.
Throughout the duration of the eclipse, clouds maintain their absence.
This is the anticipated scenario by scientists in parts of Mexico, Canada, and the United States during the total solar eclipse on April 8. If the weather allows, observers in the 49 US states expected to witness a partial eclipse may also notice some clouds disappearing.
The reason behind this phenomenon is: During an eclipse, low cumulus clouds begin to dissolve in large numbers even when just a small portion of the sun is masked. They don’t reappear until the event concludes, according to a study published on February 12, in the journal Nature Communications Earth & Environment. The researchers concluded that cumulus cloud reduction during eclipses is a result of the connection between sunlight and cloud formation processes.
Under the moon’s shadow during an eclipse, the surface gets chilled rapidly as light from the sun gets obstructed. This prevents the ascension of warm air from the Earth’s surface, a key element in the creation of cumulus clouds, explains Victor Trees, a PhD student in the Netherlands and the leader of the study. Normally, this process of air rise that leads to cloud creation takes about 15 to 20 minutes, as per the simulations.
However, this doesn’t guarantee a clear view of the upcoming eclipse as this research only applies to the low cumulus clouds that are usually found over land.
![People watch the solar eclipse in Hopkinsville, Kentucky, on August 21, 2017.](https://dynaimage.cdn.cnn.com/cnn/digital-images/org/b0a5c779-83a2-42c9-bd50-2d6a57ba6f68.jpg)
It’s midday, and the sun is high in the sky, a natural cyan canvas peppered with puffy, cauliflower-shaped clouds. With little warning, the clouds cluttering the horizon start to vanish before your eyes. Not long after, the world begins to darken, as the sun disappears from view.
For the entirety of the eclipse, the clouds will stay away.
That’s at least what scientists expect to take place in swaths of Mexico, Canada and the United States during April 8’s total solar eclipse. If weather permits, those living in the 49 US states where a partial eclipse is expected could also spot some clouds vanishing.
Here’s why that is: During an eclipse, shallow cumulus clouds start dissipating in large proportions when only a fraction of the sun is covered, and they don’t reform until the end of the event, according to a study published February 12 in the journal Nature Communications Earth & Environment. The research team found that cumulus clouds dissipate during eclipses because of the relationship between solar radiation and the formation processes of the clouds.
During an eclipse, the surface cools rapidly from the moon’s shadow blocking the sunlight, preventing warm air from rising from Earth’s surface — a core ingredient in the formation of cumulus clouds, according to Victor Trees, a doctoral candidate in the Netherlands who led the study. That rising air process leading to the production of clouds usually takes roughly 15 to 20 minutes, according to simulations.
But this doesn’t mean your vantage point of the forthcoming eclipse is guaranteed to be cloud-free as the research doesn’t apply to all clouds — only the shallow cumulus kind found hovering over land.