The sophisticated modeling behind the visualization may provide better tools for getting people out of the way of wildfires
This animation of the Camp Fire is one of the tools used by scientists at the National Center for Atmospheric Research to study factors that made the wildfire so deadly.
Driven forward at breakneck speed by bone-dry winds, California’s Camp Fire blazed down out of the hills so quickly that the town of Paradise never really stood a chance.
In the animation above, you can get a good sense of how those winds blew the fire across Paradise and other towns. Scientist Janice Coen and her colleagues at the National Center for Atmospheric Research are using it to study the factors that made the rampaging blaze so deadly. It may also help point toward better tools for enabling emergency managers to get people out of the way of chaotic, fast-moving blazes.
The Camp Fire shows how badly such tools are needed. It killed 86 people, which makes it the seventh deadliest wildfire in U.S. history, and the 14th deadliest worldwide. The fire also incinerated 14,500 residential and commercial buildings, making it the most destructive wildfire in California history.
The animation was produced using a system that combines modeling of wildfire behavior with numerical weather prediction modeling. In addition to portraying the spread and intensity of the fire, the simulation depicts the wind field. The arrows show which way winds were blowing; their length and color correspond to speed. (Check out the bottom of the two keys at upper right for the color coding that corresponds to wind speeds.)
As the simulation progresses, the colors help us visualize gusts blowing over the landscape — which are themselves influenced by the wildfire itself. Look for wave-like patterns depicted in orange and red before the fire gets going. These are wind gusts. Once the fire begins, some of those gusts — the ones represented by the darkest reds — reach speeds of 40 meters per second. That’s almost 90 miles per hour!
Also, to get a sense of just how fast the Camp Fire raced into the town of Paradise, consider that each of the tick marks along the horizontal and vertical axes are 20 miles across.
Firefighters arrived on the scene shortly after the fire began — at 6:43 a.m. on Nov. 8, 2018. They found the blaze already moving very quickly. Cal Fire spokesperson Scott McClean described it this way: “This fire is moving football-field lengths within seconds.”
In just over an hour, the fire had already reached Paradise.
Butte County officials have been criticized for not issuing what’s called a Wireless Emergency Alert, or WEA, which is like an Amber alert in that it reaches most cellphones in a particular area. That might have helped. But the plain fact is that this fire moved with breathtaking speed.
“You have to keep in mind that this was an extraordinarily chaotic and rapidly moving situation,” said Butte County Sheriff Kory L. Honea, quoted by NBC News. “The fire started in a remote area. It takes awhile for our fire resources to get there and from that point, trying to determine the path of travel and whether or not that’s going to effect populated areas, that takes time,” Honea said.
And that’s precisely how simulations like the one above might help with future fires.
As an NCAR description of the system used to produce the visualization puts it:
To safely manage wildland fires, decision makers need reliable, accurate, frequently updated, easily accessible, geo-referenced information about current and predicted weather and fire behavior. With such information, decision makers can better determine how a fire is behaving now and might behave in the future. Reliable information about the potential for a fire to spread rapidly and behave erratically is essential for saving life and property.
Current systems for predicting how wildland fires will move and behave are not coupled to weather prediction models. That’s a problem because this leaves out details affecting the winds, such as outflows from storms, complex terrain, and the passage of weather fronts.
Also, large wildfires feed back on weather conditions by generating strong updrafts and intense local winds that can push the flames across the landscape even harder, and in new directions. Moreover, particles and moisture billowing up from large wildfires can create towering fire clouds, known as “pyrocumulus clouds,” which in turn impact local conditions.
“The modification of the winds by the fire is the cause of virtually all phenomena that create the individual character of [a] large event,” according to NCAR.
As suggested by the name of the system used by the NCAR researchers to produce the Camp Fire simulation — the Coupled Atmosphere-Wildland Fire Environment, or CAWFE — the necessary coupling was built in. With that coupling, CAWFE can show how both weather and wildfire interact in complex terrain, simulating the progression of a fire in time and space. The hope is that it can be used to design prediction systems with the precision and speed necessary to help emergency management personnel make better, more timely decisions.
Thanks in part to the backdrop of long-term climate change that has been contributing to more frequent large wildfires in the West, the need for such systems will only increase in coming years.