Mountain weather has so many anomalies.

For example, a common assumption is that the air always grows cooler the higher the altitude, but that isn’t always true. During a temperature inversion, colder air may settle to the valleys below and warmer temperatures can be found at the higher elevation.

An inversion isn’t unusual. In fact, on calm evenings without any other outside influence, it’s a regular occurrence, particularly at night without the radiant heat from the sun.

Which brings us to today’s vocabulary words.

At night, as the sun sets, the air at the highest elevation naturally cools. When it does, it sinks and slides down the surface of the mountains into the valleys below. These are known as katabatic winds. In the morning, the sun heats that air in the valley and it rises, creating anabatic winds going up the mountain face to the peaks.

As is so often the case, the words trace back to Greek—katabatos means descending and anabatikos means ascending.

Next time you find yourself in the mountains at sunrise or sunset, you can impress your friends by talking about the katabatic (downslope) or anabatic (upslope) winds.