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

Question

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

Answer 1

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.