eli5: why do the clouds form in a straight line sometimes?



sometimes when youre looking at the sky, the clouds will be puffy at the top, but at the bottom it looks like someone just took a knife and chopped the bottom off so the clouds are completely in a straight line at the bottom

In: Earth Science

Many clouds are roughly flat on the bottom because of air temperatures and densities. Clouds are condensed water droplets. As warm/moist air rises the moisture is still in vapor. Once it reaches a temperature where it can condense into droplets, it will. In our atmosphere air temperature correlates very heavily with altitude. So as the warm air climbs, it hits a horizontal plane where condensation now occurs. That keeps the bottom of the clouds flat because that’s the altitude where condensation is occurring.

As warm air rises the pressure drops, since there is now less air pressing down on it.

This allows the air to expand, causing the temperature to drop.

Once the temperature drops enough, the water gas condenses, forming fine liquid drops.. the mist of a cloud.

Since this temperature change is strongly influenced by height, this transition occurs at a specific height, giving you the flat bottom.

You can get a flat top, when the cloud rises high enough to strike the stratosphere, the next layer of the atmosphere.

Furthermore you can get a line if clouds, as a warm air and cold air front meet, again forming a sharp transition point.