Fog is a collection of liquid water droplets or ice crystals suspended in the air at or near the Earth's surface. While fog is a type of stratus cloud, the term "fog" is typically distinguished from the more generic term "cloud" in that fog is low-lying, and the moisture in the fog is often generated locally (such as from a nearby body of water, like a lake or the ocean, or from nearby moist ground or marshes). Fog is distinguished from mist only by its density, as expressed in the resulting decrease in visibility: Fog reduces visibility to less than 1 km, whereas mist reduces visibility to no less than 1 km . For aviation purposes in the UK, a visibility of less than 5 km but greater than 999 m is considered to be mist if the relative humidity is 70% or greater – below 70% haze is reported.
We don't often experience fog in Melbourne, but occasionally it does blanket the city in winter as it did earlier this week. It can give opportunity for some nice photos. They are from my local train station early in the morning, then the Southern Cross station in the city and then while walking to work up Bourke St.
You can find more of my photos in the fog from last year, here.
This post is part of the Skywatch Friday meme.