Closely Built Homes Help Spread Colorado Marshall Fire

Too many houses built too close together on the tinder-dry high plains between Denver and Boulder resulted in $1 billion in Marshall firestorm losses, insurance industry researchers discovered this week as they sifted through ashes and charred ruins.

Source: Reporter-Herald | Published on January 19, 2022

High winds 80 to 100 miles per hour fueled apocalyptic wild fires which tore across open grasslands and through homes in Superior, Colorado off highway 36. Power was cut to 34,000 homes and over 30,000 residents were forced to evacuate. Over 500 homes were destroyed by the Marshall fire outside Boulder, Colorado which was sparked by downed power lines in high winds on December 30, 2021.

They were starting an investigation, similar to the work done after previous devastating fires, such as the Waldo Canyon fire west of Colorado Springs in 2012 and the 2018 fire in Paradise, California, which destroyed nearly 19,000 structures. Their industry, the Insurance Institute for Building and Home Safety, is researching how fires spread through communities and what can survive as climate change worsens.

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

Another issue was the firestorm's proximity to native vegetation — grasslands where record high temperatures and drought had created conditions in which, with human ignition and high winds, the firestorm spread quickly from Marshall into suburban-built Superior and Louisville, according to research engineer Dan Gorham.

"This is an ecosystem that has evolved to include fire." "We'll have to learn to live with it," Gorham said, pointing to the grasslands between Superior and Boulder. "We must construct with the understanding that this is an ecosystem that requires fire."

As the industry team roved through this Sycamore development where construction took off in the 1990s, devastated homeowners stood in ash and ruins, masked to reduce their inhalation of toxic metallic fumes from burned appliances. They discussed what happened on December 30 and agreed on the importance of building resilience for the future.

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

A neighboring house was only about 10 feet away. And Vigh was conducting his own investigation, donning a respirator and plastic white overalls and looking for a computer hard drive containing family photos. He discovered it in basement foundations, hunched over it, only to discover that it had burned too much and that the images had been lost.

He's now wondering if the owner of the adjacent house would be willing to sell so that his family could have more space in the future. "If he doesn't rebuild, I'd consider buying his property," Vigh said.

In the aftermath of the most expensive climate-induced inferno in state history, a renewed Colorado push for "hardening," now in suburbs as well as mountain forest developments, is gaining traction. The Marshall firestorm destroyed 1,084 structures and damaged at least 149 others, including a Super Target where wind-whipped embers discovered 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 Gov. Jared Polis' Colorado Fire Commission, which is tasked with addressing wildfire risks.

"We'll have to start from scratch."

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

Closer spacing and vegetation management for fire protection may conflict with water conservation and other long-term goals, according to Molly Mowery, director of the Community Wildfire Planning Center, a non-profit that advises local officials.

Looking at growth limits opens "a huge can of worms," according to Mowery, who anticipates that increasing fire resilience will necessitate balancing climate change preparedness measures. "There will not be a solution that satisfies everyone."

Researchers from the insurance industry determined that the Marshall firestorm accelerated as it spread from grasslands to houses 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 close," said Roy Wright, CEO of the Insurance Institute, as his team began their investigation on Thursday.

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

Remaking Colorado suburbs to withstand worsening fires will also necessitate clearing buffers at least five feet wide and "impeccably" bare, as well as screens on vents and retrofitting with non-flammable roofing, siding, and vegetation, according to Wright. Green lawns that are well-watered are less likely to burn than native grasses, he claims.

And the mulch that residents are increasingly using to help plants withstand rising temperatures is "like spreading match sticks around your house."

Officials from the insurance industry also suggested reconsidering the "Wildland Urban Interface" concept, which Colorado officials have used in mapping urban development as it increases in forests to prioritize fire protection.

"We have to start imagining what we see here as likely.....," Wright said. "We have a skewed view of where the wildlife risk exists."

In recent years, Colorado public safety officials have focused on increasing the state's ability to quickly suppress wildfires in forests. However, as the climate warms, they will face more winter grassfires. In addition, aggressive forest fire suppression has resulted in overly dense forests that are ready to burn. Some members of the state fire commission are talking more about land use and improved defenses for dealing with larger fires, which they believe will become more common as temperatures rise over the next 20 years.

Walker described Colorado and much of the West as being trapped in a cycle of "escalating catastrophes."

Walker predicts that insurers across the state will increasingly demand vegetation-free buffers around homes, asphalt-shingle or metal roofs, screened-off vents, and other defenses.

"The science tells us that there's a lot you can do to tip the odds in your favor with most wildfires," she said. "With the increasing number of fires, it will become a matter of insurance availability and affordability." …. Insurance will require you to make your home more secure. If your risk is higher, you will most likely pay a higher rate."