What Causes ‘Super Fog’ and Can It Happen in Washington & Oregon?

You may have seen the story coming out of Louisiana where over 158 vehicles were involved in a crash around 9 am central time this morning.  When it was over, seven people lost their lives, over 25 were transported to the hospital from the scene, while a number of other sought medical attention on their own.

Get our free mobile app

The crash happened on Interstate 55 in St. John the Baptist Parish, around 30 miles northwest of New Orleans.  Video from the scene shows a horrific stretch of mangled vehicles spanning miles.

Reading further about the cause, the term 'super fog' was introduced.  It was something I had never heard before.

What is 'Super Fog'

The National Weather Service (NWS) describes 'super fog' as:

"a mixture of smoke and moisture released from damp smoldering organic material such as brush, leaves and trees, mixes with cooler, nearly saturated air."

In short, if there is burning material in an area and the smoke from that mixes with moisture in cooler temperatures, you get a cocktail that lowers visibility to less than ten feet, and was most likely at zero for long stretches..  It creates an untenable driving situation that results in what happened this morning over a six hour stretch of time.

The Federal Highway Administration attributes over 38,700 accidents a year to foggy conditions.  Last year a 'super fog' situation claimed three lives in Florida.  Ten people died just over a decade ago in another Florida accident where 'super fog' was a factor.

This Can't Happen in Washington and Oregon Though...

It very much can.  It can happen anywhere.  While a number of these accidents have happened in the South, it really depends on the right combination of elements at the wrong time.  The U.S Department of Agriculture, in a report, discussed what is released into the air from wildfires and other agriculture burns and how it can create a 'super fog'.

Imagine one of the many passes or forest areas on the west side of the state.  Imagine an early spring or late fall wildfire during lower temperatures in areas of dampness.  The closest Washington State has come to this phenomenon happened in September of 2020.  Wildfire smoke from Oregon moved up to Washington State.

On September 10th, the cooler temps brought the smoke closer to ground level.  While we didn't reach the 'super fog' classification, much of the State was blanketed with smoke for nearly a week, creating air quality and visibility issues.