Super fog: What is it, what causes it, and can you drive through it?

The morning rush hour on Interstate 95 was brought to a stop on March 3, 2022, after a thick wall of fog and smoke – known as "super fog" – cut visibility on the freeway to less than 10 feet. In the end, 17 vehicles were part of five separate crashes – and three people died.

What is super fog? What causes it? And if you're on the road, and it happens, what should you do? In terms of the crash, why weren't any warnings given earlier?

Super fog is caused when smoke and steam from burning or smoldering wetlands mix with overnight fog – making it visually almost impenetrable. This can make it impossible to see even directly in front or behind you.

On the freeway – where cars travel 50+ mph – that can be incredibly dangerous."

What caused the super fog on March 3?

Turns out, officials had authorized the burning of a 161-acre track of private land west of I-95 near Edgewater. The "controlled" or "prescribed" fire is meant to burn excess brush to eliminate fuels that could spark into a larger and out-of-control wildfire, according to Florida Forest Service.

"If we get out ahead of the wildfires, and we do the prescribed burning and everything, it reduces that fuel," said Travis McGowen, the FFS Forestry Area Supervisor for Seminole County.

What would happen if prescribed burning didn't happen? "The wildfire threat would go through the roof," he said.

So, what happened on March 3?

In my investigation, there were two main problems: the weather forecast changed – it initially didn't call for fog, then did – and the FFS made their decision to conduct a prescribed burn based on a broad forecast vs. one that focused on the area of the burn.

The result: smoke mixed with saturated air, which resulted in a blanket of dense hard-to-see-through fog on the freeway during the morning commute.

The burn was authorized on March 2 by FSS – and there wasn't fog expected in the forecast at the time, according to National Weather Service's Melbourne Office.

"We consult with the National Weather Service every day. That's where we get our weather reports from (and) that's where we decide if the weather is going to work with us to do a prescribed fire," said Cliff Fraser, who works for Florida Forest Service.

"We can get the weather report from the National Weather Service the night before, and the next day it may change, you know? It's like the weatherman telling you it's going to rain tomorrow and it don't rain, you know?"

Yes. He was right.

Fog wasn't in the forecast on March 2. It wasn't included in the forecast until that evening, 12 hours after the prescribed burn had been lit. With hours of burning and smoke from trees, leaves, and brush in the area, the damage was done.

On to the second concern – the regional forecast vs. a spot forecast.

NWS policy indicates that spot forecasts – forecasts for a specific area – are provided only for public events and burns on public lands. This burn was conducted on burn on private land was not qualified to receive the benefit of these more accurate forecasts.

Simply put, NWS cannot provide spot forecasts for private burns.

FFS did not attempt to acquire a spot forecast for the burn, FOX 35 learned, and NWS would not have provided one if it had, citing its policy.

What did the forecast indicate?

The forecast winds and smoke dispersion on the publicly-available NWS weather outlook indicated it would be safe to burn. That forecast was ultimately different than what was observed near the burn site.

Instead of smoke drifting away from the interstate as was initially forecast, it drifted over it, putting unknowing drivers in a very dangerous – and ultimately, deadly situation.

It's possible that a spot forecast for this specific burn site location – a look at local winds, fog and smoke dispersion – would have indicated potential concerns. However, no one can predict exactly whether addressing both those issues would have prevented the March 3 event.

Still, with 23 people killed and more than 100 people injured in super fog-related events in Florida over the past 22 years, it suggests that additional safety measures may need to be considered.

What should you do if you're on the road and go through dense fog or super fog?

  • First, don't panic and do not stop in the road.
  • Gradually slow down and avoid sudden braking unless you're forced to.
  • Turn on your headlights so your taillights are activated. Turn off your radio and roll down the windows because you may need to hear what's happening around you.
  • If the fog is too thick and you want to stop, pull off the road as far as you can. Only then should you activate your hazard light flashers.
  • While it's not unlawful to drive with your hazards on, it's not recommended because for years hazards meant the driver was stopped and so it could confuse those behind you.
  • Only once you feel safe, call 911 in case they have not been made aware of the super fog.