Thermal inversion

In a typical weather scenario, air temperature decreases as elevation increases. With thermal inversion, it’s the opposite: it gets warmer as you get higher.

During the day, the mountaintops are cooler than the valleys. But once the sun goes down, that denser cold air on top starts to sink into the valley. If conditions are exactly right, the cold air will mix with moisture in the air to form a sea of clouds by morning, presenting a remarkable sight for anyone awake at sunrise.

Thermal inversions can develop in many places around the world. However, the combination of topography and climate in western North Carolina offers some of the most wonderful chances to witness it.