The science is settled. The gap isn’t closed.

Fire researchers have understood how homes actually ignite for roughly thirty years. Here’s what that science says, what’s been done with it so far, and where it still falls short.

The scale

  • 44 million+Homes in the U.S. now sit inside the Wildland-Urban Interface — the zone where wildland vegetation and residential development meet.
  • 47% Growth in the number of WUI homes between 1990 and 2020 — one of the fastest-growing land-use patterns in the country.
  • 54% Of California wildfire-destroyed homes sit in lower-income communities, where hardening upgrades measurably lag furthest behind.

The science

For most of the 20th century, wildfire policy treated home loss as a fire-intensity problem: bigger, faster fires meant more destruction, so the answer was better suppression. That assumption started to break down in the late 1980s, when a U.S. Forest Service researcher named Jack Cohen began investigating something that seemed almost too simple to matter: what actually makes one specific home catch fire, while the one next door doesn’t?

In 1997, Cohen ran an experiment that reframed the field. He ignited blocks of forest next to wooden test structures placed 33, 66, and 98 feet from the flames. The structure 33 feet away ignited on every side. The one at 66 feet only charred on one. That gap — a factor of two in distance separating total loss from minor scorching — pointed to something counterintuitive: it’s rarely the wall of flame itself that destroys a home. It’s what happens in the last 100 to 200 feet around it, mostly from windblown embers lofted ahead of the fire, landing in gutters, vents, roof valleys, and anything combustible within a few feet of the walls.

Cohen called this the Home Ignition Zone. The finding has held up in nearly every major post-fire investigation since, including the Tubbs Fire, the Camp Fire, and the 2025 Palisades and Eaton fires. It reframes wildfire home loss as a structure-ignition problem rather than a fire-intensity problem — a distinction that matters, because it means home survival is something that can be engineered for, largely independent of how big or fast the fire itself is.

What the science tells us

  • It’s rarely direct flame contact.
  • Embers lofted ahead of the fire — sometimes more than a mile — cause most home ignitions, not the advancing fire line itself.
  • Distance and detail decide the outcome, not fire size.
  • A few feet of clearance and a handful of overlooked gaps are often the entire margin between a home that survives and one that doesn’t.
  • The zone that matters most is small.
  • Home ignition potential is determined mostly within 100–200 feet of the structure — an area a homeowner, builder, or technology can actually influence.

What’s already being done

Defensible space & vegetation management

Programs like Firewise USA and CAL FIRE’s Ready for Wildfire ask homeowners to clear flammable material and manage vegetation around a home. It’s foundational, low-cost, and grounded in the same research — but it depends on being done, and redone, every season.

Home hardening

Class A fire-rated roofing, ember-resistant vents tested to ASTM E2886, and noncombustible material in the first five feet of the structure — often called “Zone 0.” These target the exact ignition pathways Cohen’s research identified.

Third-party certification

IBHS’s Wildfire Prepared Home program, launched in 2022, verifies these upgrades against a science-based standard. It’s now available in 14 states, with some insurers offering premium discounts of 5–35% to certified homes.

Building codes

States including California and Colorado now require wildfire-resistant construction for new homes in the WUI, consolidating decades of research into enforceable standards.

Exterior sprinkler & misting systems

Aftermarket systems that wet a structure and its surroundings ahead of a fire’s arrival, typically used as a supplemental layer alongside hardening and defensible space.

Where it falls short

Defensible space

Requires labor and vigilance every single year, not a one-time fix. A gutter full of dry leaves or one missed season can undo the investment, and compliance is inconsistently enforced and hard to verify at scale.

Home hardening

Effective, but adoption tracks income. Lower-income communities see measurably fewer roof renewals and are documented to be more likely to lose homes as a result. A full retrofit can run from a few thousand dollars to nearly $100,000 depending on scope.

Certification

The strongest science-backed signal available today still covers a rounding error of the exposure — roughly 1,400 homes certified nationwide against more than 44 million homes in the WUI. It’s also voluntary and inspection-dependent.

Building codes

Only two states had a mandatory statewide WUI building code as of April 2026. Codes also govern new construction — they do almost nothing for the tens of millions of homes already standing, built under older assumptions about how fire behaves. Even California’s own hardening mandate for existing homes has been delayed past its original target.

Exterior sprinklers

Built around an assumption that often doesn’t hold in the moment that matters most. Most require someone to manually activate them during an evacuation, many municipalities prohibit connecting them to shared water supplies, power outages disable pumps unless independently powered, and fire-driven winds recorded above 100 mph can simply blow the water away. IBHS has said it doesn’t yet have data to estimate their effectiveness.

The gap, stated plainly

Put together, this is the shape of the gap: the science has been settled for roughly thirty years. The standards exist, they’re getting stronger, and they work when they’re in place. But almost none of the homes that need them have them — and the solutions that come closest either depend on a homeowner doing the right maintenance every single season, or on power and water infrastructure that’s often exactly what fails during the fire itself.

1,400 Homes nationwide have earned IBHS’s science-based Wildfire Prepared Home certification, as of early 2026.

44,000,000+Homes sit inside the Wildland-Urban Interface today.

Where Pyrskene fits

This is the gap we started Pyrskene to close: technology built specifically for the Home Ignition Zone — the last-mile, structure-level ignition pathways this research identifies — rather than the fire as a whole. We’re designing for the homes that already exist, not just the next generation of new construction, and we’re not willing to depend on something that needs a person to remember to switch it on, or a power grid and water main that are often the first things to fail. We’re not ready to share how yet. But now you know why.

Want the category, not just the science?

Our Approach page lays out where we’re focused, without the mechanism.

See our approach

Notes & sources