"If the fuels data is good, if the weather data is good and the location is correct, our models provide a good ballpark," said Technosylva President Joaquin Ramirez. "It's a young science, but we're on the right track."
Difficulties remain in accurately predicting extreme fire behavior, however.
When the federally managed North Complex fire jumped a river and sped into Berry Creek on Sept. 8, killing more than a dozen people, "the spot fire moved 20 miles beyond all models identified," the fire's incident commander, Jay Kurth, wrote in a public letter.
Similarly, when SDG&E tried to re-create simulations of large fires they experienced in 2003 and 2007, Technosylva's models were less extreme than what actually happened. While the Technosylva software uses data more refined than its competition, experts say the fundamental science behind predicting what a fire will do hasn't changed, more or less, in half a century.
"There's really only one model that's used for fire spread models - it's the Rothermel model," said Chris Lautenberger, co-founder of fire spread modeling company Reax Engineering, which also holds a contract with PG&E. "Technosylva uses that, our model uses that. So what differs from model to model is more the assumptions and approximations that are made."
The Rothermel model is a mathematical equation established in 1972 by a former General Electric engineer to explain the rate of a fire's spread. It models ground fires in light brush and grass, and has become the foundation upon which most fire predictive models - from crown fires to fire spotting - were built.
"My model has lasted through 50 years because it could do the work," Richard Rothermel, 90, told the Los Angeles Times in a recent interview from his Montana home. "Now, the problem is people expected it to do far more than it was designed to do."
With that in mind, officials with all three utilities said that while they're using fire spread modeling to inform their power shutoffs, it's not the deciding factor.
"If you're looking for a dead-on representation of the footprint of that fire, it's going to be off," said Edison's fire scientist, Tom Rolinski. "It's a model, and all models are wrong. We just don't know where they're wrong."
Visit the Los Angeles Times at www.latimes.com(c)2020 Los Angeles Times, Distributed by Tribune Content Agency, LLC.