Wildfire risk in the City of Louisville is driven by a convergence of grassland fuels, extreme wind events, dense development patterns, and interconnected neighborhoods. The 2021 Marshall Fire demonstrated that wildfire impacts in Louisville can rapidly escalate into urban conflagrations, where structure-to-structure fire spread overwhelms suppression capacity and results in widespread losses. This Wildfire and Conflagration Risk Assessment was developed to better understand these risks and identify actionable strategies to reduce structure ignition, improve preparedness, and support long-term community resilience.
This comes jointly from the Louisville fire department and The Ember Alliance. The Louisville Fire department also gives further summaries and context.
Wildfire Partners, Nyland Assessment
Wiley’s notes from the meeting with Abby from Wildfire Partners, on 2025 Aug 1.
This describes Wildfire Partners’ recommendations for hardening Nyland against fires, while and after touring the neighborhood.
For what it’s worth, and of course this is hardly a primary source, but I had a useful-to-me discussion with Claude on several of these topics. Taking Claude as an expert here is probably not the right move, but there are lots of available citations also in that chat.
My key takeaways from that conversation:
There’s no ideal data on juniper flammability – but that just means that ideal evidence isn’t available. Of the evidence we do have, we really should expect that junipers, in a conflagration, will catch fire more quickly, burn hotter, and cast more embers than any other plants.
The “green gasoline” motto is pretty much just hyperbole. “Like a barrel of gasoline catching fire” is just not a true or useful mental image for a juniper on fire.
Home hardening, removing all combustible materials 5 feet or less from a house, and replacing wood structures like fences and decks with noncombustible materials, are all likely to be more impactful to house damages than any sort of landscape + vegetation management further from the home, especially if we’re most worried about increased risk due to to high-wind wildfires.
Note, though, that this speaks only to risks of structural damage, and not other fire considerations like people’s safe movement through the community in an emergency.
There is no solid, common quantitative framework for discussing a home’s risk of damage due to fire. I doubt we have even order-of-magnitude-accurate estimates for how much different mitigation efforts would change our risk.
Thanks to Matt for putting this online. A couple things I’ve found helpful in how we frame this and try to find a comfortable middle ground with risk management. This article, in the very wonky “Fire Technology” https://link.springer.com/article/10.1007/s10694-024-01616-7#Bib1, is an analysis of the Marshall Fire. One key takeaway from my reading is that a substantial amount of our fire risk is baked into multiple factors that are outside of our control: the age and materials of our houses, the density of our development, and the realities of climate change. The article concludes that “…in communities with high density of homes, the houses themselves are much larger conduits for fire propagation than the vegetation surrounding them on their parcel…” It stated that wooden fences, vegetation overhanging the house, and vegetation within 5’ of the perimeter were much stronger predictors of Marshall Fire destruction than the presence or absence of junipers or any specific vegetation. The Insurance Institute for Business & Home safety also published a white paper https://ibhs.org/wp-content/uploads/Suburban_Wildfire_Conflagration_WhitePaper.pdf that reached some similar conclusions. The main point I draw from these studies is that we are only likely to minimally reduce our already low risk of catastrophic fire by removing our junipers. That does not mean we shouldn’t do it. I think we need to carefully consider the social aspects of our decisions because I am not sure we can reach one grounded in science-based risk management alone.
Matt asked me to summarize key takeaways from the fire mitigation expo in Longmont, 4/4/26 which 7 Nylanders attended. This was basically a trade show with vendors educating the public about fire mitigation strategies. Mostly very expensive home hardening techniques…but also mitigation experts sharing experience and helpful tactics. They all shared a cumulative, broad approach. We live in a “wildland urban interface” so do all you can:
Structure hardening (vent and gutter covers, etc)
Critical area is 0-5 feet from home:
no plants, wood mulch, junipers touching foundation; use rock, gravel or pavers in this strip
no firewood, lumber, furniture, debris under decks or next to siding
Xcel Backup Battery Rebate Program Whole home battery provides power for medical equipment during temporary Public Safety Power Shutoffs xcelenergy.com/Wildfire
And other companies that provide integrated power backup (battery, generator, solar, EV charger) www.riscopower.com
Insurance Support for disaster recovery/or if you’re dropped by your home insurer United Policyholders (UP) is a non-profit 501(c)(3) www.uphelp.org
Companies advertising:
roof & gutter protection (install Class A fire-rated roofing materials; ember-stopping gutter guards)
vents & openings sealing (cover all vents with 1/8-inch non-combustible corrosion-resistant mesh or upgrade to ember-resistant vent designs; seal gaps around doors, windows, garage entries)
fire resistant exterior remodeling for walls, windows & decks (non-combustible siding like stucco, lightweight fiber cement; multi-pane, tempered glass windows; ignition-resistant deck materials)
fire retardant spray–when material home hardening replacement isn’t an option. For landscape, wood treatment (fences, decks, siding)