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Thursday, March 19, 2009
Super Fog – Tips For Dealing With A Dangerous Weather Phenomenon
As we enter into the spring time, which is a drier period in the south, the forest fire emergency levels will increase. The fire season presents some unique problems due to a little known weather phenomenon called "Super Fog". Super fog is not limited to the south but the weather conditions, namely high humidity, normally prevalent in the southern part of the US, makes the area more prone to the phenomenon.
To understand super fog we have to look at how smoke from wildfires or controlled burns can create the conditions for a super fog.
Smoke and ash from a burn mix with the humidity in the air forming tiny droplets around each speck of ash or solid contaminant produced by the fire. As the droplets accumulate, the smoke turns into a combination of smoke and fog creating a super fog that can form as an almost solid wall with visibility reduced to near zero. Super fog appears most often at night and forms most readily at a low level over creek and river beds. While it most often forms at night, it is usually at its heaviest in the early morning hours before the heat of the sun can burn it off. That means it is present most often during the morning rush hour. The problem with super fog is that it is almost impossible for weather forecasters and scientists to predict because the local winds at night are unpredictable and the super fog can form more than 20 to 30 miles away from the site of the fire.
Super fog is especially dangerous on high-speed highways and interstates when cars and trucks, traveling at high rates of speed enter into an almost zero visibility situation that can cover the highway for miles. The inability of cars and trucks to see each other and to slow or stop at the same rate of speed creates a critically dangerous situation. In January of 2008, a controlled burn in central Florida created a super fog event that blanketed Interstate - 4 west of Orlando. Cars and trucks entering the fog began crashing into one another leading to a pile-up that ultimately involved 70 vehicles, 38 injuries and 4 deaths. Another fog related pile-up in California in 2007 involved 100 vehicles resulting in 2 deaths.
Super fogs are impossible to predict and it is impossible to predict when they may lift or how far away from the actual fire they can occur. How can you avoid getting trapped in a super-fog?