Around the Brazos Valley, we have seen several foggy mornings and days. It comes with the territory of being in a more humid environment. Although fog looks the same anywhere it forms, there are multiple reasons why we see it. In this blog, we discover what evaporation fog is and how it forms.

Evaporation fog forms when enough warm, moist air in the form of water vapor evaporates into the air and mixes with colder, drier air. There are two different kinds of evaporation fog: steam and frontal.

Steam fog is what is normally seen over a pond or lake. Since the body of water is generally warm, if colder air moves over that water, the moist air will start condensing. Once the air reaches 100% humidity, fog is formed. Steam fog normally looks like smoke is rising from the water.

Frontal fog occurs when warm raindrops evaporate into a layer of cooler, drier air near the surface. Once enough rain evaporates near the surface and humidity reaches 100%, for is formed. This can happen with any kind of front: cold, warm, or occluded.

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