My morning drive

Where I currently live there is a often fog in the morning and evenings. Last week we had fog roll in that stuck around for a couple of days. Ever since I was a kid, I've liked the look of fog and they way it shrouds everything, obscuring an object from view until you reach that magical distance and can see it again. As a kid it was amazing. As a driver it is always harrowing. Yet still the kid in me marvels at the fog. I love the way it settles in valleys and riles in the landscape and hugs the ground. It is a gas that acts like a liquid, not because of properties inherit to itself, but because of external factors.

First, what causes fog to form?

Actually, that's a tricky question because there are different types of fog. NOAA (National Oceanic and Atmospheric Administration) lists 6 types of fog and they are all have a different event that causes them.

"What is fog?" is a lot easier to answer. Fog is simply when the air is supersaturated with water droplets. These droplets, depending on their size and consistency obscure vision can transfer their moisture to objects they touch. In short: Fog is a cloud that likes to hang around at ground level. The situations that causes this low-hanging cloud to form are described in the NOAA link above.

For our part, I believe the fog we get most regularly is the standard radiation fog. It happens more often because of the wetlands near us. The large amount of surface water means that the humidity near ground level is higher than many other areas I've been in, thus allowing the air to supersaturate very quickly.

The fog we had last week, I believe was was probably ice fog. I don't know about it occurring only in polar/arctic air if it just takes really cold temperatures to cause it. We had a series of days where the temperature was well below freezing, even reaching below zero Fahrenheit. One evening while driving to dinner (where we got the fortune cookies I blogged about), visibility was between 100-200 ft. you could not see more than two street lights - the one you were under and the next one.

Granted, after viewing the movie based on Steven King's The Mist, some think that the weather isn't the only cause of fog...