‘Spacing Here Was A Problem’: Close Homes Helped Marshall Firestorm Spread

They were beginning an investigation, similar to work done after previous ruinous fires, including the 2012 Waldo Canyon fire west of Colorado Springs and the 2018 fire that destroyed nearly 19,000 structures in Paradise, California. Their industry Insurance Institute for Building and Home Safety is developing a science of how fires burn through communities and what can survive as climate warming intensifies.

"Spacing here was a problem, " research engineer Faraz Hedayati said as he probed gaps less than 10 feet wide between former houses where radiant heat helped flames spread.

Another problem was proximity to native vegetation — grasslands where record high temperatures and drought had created conditions where, with human ignition and high winds, the firestorm spread rapidly from Marshall into suburban-built Superior and Louisville, research engineer Dan Gorham said.

"This is an ecosystem evolved to have fire. We need to learn to live with that," Gorham said, pointing to the grasslands between Superior and Boulder. "We need to build with an understanding that this is an ecosystem that needs fire."

Devastated homeowners stood in ash and ruins, masked to reduce their inhalation of toxic metallic fumes from burned appliances, as the industry team roved through this Sagamore development where construction took off in the 1990s. They shared accounts of what happened on Dec. 30 and embraced the idea of boosting resilience for the future.

"I definitely want to build back better. I want to know the right way," said Jonathan Vigh, 44, an atmospheric scientist who fled with wife and two children as reddish-hued smoke from the immediately adjacent grasslands billowed toward their house. A few asphalt shingles from their roof endured, and a pear tree planted in 2015 survived, but a cedar fence apparently functioned as a wick and the destruction was total.

A neighboring house sat less than 10 feet away. And Vigh was conducting an investigation of his own, wearing a respirator and plastic white overalls, searching for a computer hard drive that contained family photos. He found it in basement foundations, hunched over it, only to see it had burned too much and that those images were lost.

He's now wondering whether the owner of that adjacent house might be willing to sell so that greater spacing would be possible for his family in the future. "If he chooses not to rebuild, I would think about buying his property," Vigh said.

A renewed Colorado push for "hardening," now in suburbs as well as mountain forest developments, is gaining traction in the aftermath of this most-costly climate-induced inferno in state history. The Marshall firestorm destroyed 1,084 structures and damaged at least 149 more, including a Super Target store where wind-whipped embers found organic material on the roof.

"This could be a model re-build for us to get to a fire-safe community," said Carole Walker, director of the Rocky Mountain Insurance Information Association and a member of the Colorado Fire Commission tasked by Gov. Jared Polis with addressing wildfire risks.

"We will be starting from scratch."

The question is what hardening would entail. A fire safety push for lower-density housing would collide with a push by some planners and developers toward higher-density "mixed-use" communities. Population growth in Colorado and other parts of the arid West has led some planners to encourage housing "units" clustered tightly like integrated circuits and surrounded by native vegetation that requires less water than lawns and parks.

Closer spacing and vegetation management for fire protection could clash with water conservation and other long-term objectives, said Molly Mowery, director of the Community Wildfire Planning Center, a nonprofit that guides town officials.

Looking at limits on growth opens "a huge can of worms," Mowery said, anticipating that boosting fire resilience will require balancing climate warming preparedness measures. "There's not going to be a solution that satisfies everything."

The insurance industry researchers determined that the Marshall firestorm, as it spread from grasslands into houses, accelerated because flames found abundant fuel and radiant heat ignited closely-packed structures, adding to the ignitions from wind-whipped embers.

"Conflagration happens when you get that proximity," Roy Wright, chief executive of the insurance institute, said Thursday as his team began their investigation.

Spacing closer than 12 feet favors fire, researchers have established, and gaps between homes of 50 feet or more are advisable, Wright said. "Dispersion is one way to eliminate the domino effect" and with greater spacing "you would not have had so many structures lost."

Re-making Colorado suburbs to endure worsening fires also will require clearing buffers at least five feet wide and "impeccably" bare, Wright said, along with screens on vents and retro-fitting with non-flammable roofing, siding and vegetation. Well-watered green lawns are less likely to burn than native grasses, he said.

And the mulch that residents increasingly use to help plants endure as temperatures rise "is like spreading match sticks around your home."

Insurance industry officials also recommended a rethinking of the "Wildland Urban Interface" concept that Colorado officials have used in mapping urban development as it increases in forests to prioritize fire protection.

"We've got to start imagining what we see here as probable …..," Wright said. "We have too narrow a view of where the wildlife risk is."

Colorado public safety officials have focused in recent years on ramping up state capabilities to rapidly suppress wildfires in forests. But now as the climate warms they face increased winter grassfires. And the aggressive forest fire suppression has led to overly dense forests primed to burn. Some members of the state fire commission are talking more about land use and improved defenses for enduring worse fires, which they see as inevitable as temperatures warm over at least the next 20 years.

Colorado and much of the West is locked in a cycle "of escalating catastrophes," Walker said.

Insurers across the state increasingly will require vegetation-free buffers around homes, asphalt-shingle or metal roofs, screened-off vents and other defenses, Walker said.

"The science tells us that with most wildfires there's a lot you can do to put the odds in your favor," she said. "With the escalating fires, it will become an issue of insurance availability and affordability. …. Insurance is going to require you to make your home safer. You will likely pay a higher rate if your risk is higher."