Woo-eee! It’s fire season
Managing fire risk at the wildland-urban interface
Story and photos by Minesh Bacrania
Woo-eee is the accepted pronunciation of the acronym WUI, short for wildland-urban interface. WUI is the zone of transition between unoccupied land and human development — an area where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels, according to the US Fire Administration.
Those protected zones are likely to take on increased importance this fire season, especially because the winter of 2024-2025 was dismal, in terms of precipitation. The lack of moisture, combined with the long-term drought, has many people around Los Alamos concerned about the current fire season. While there are bigger projects around the community — like forest management, mitigation, resource allocation, etc. — each homeowner can take steps to maintain the area around their homes, and by properly maintaining these “Home Ignition Zones,” residence can reduce the risk of damage to the individual home and reduce the spread of fire through neighborhoods and the community.
To that end, the Los Alamos Fire Department has been offering free fire-risk assessments of individual properties, and Boomtown was invited to tag along with Wildland Division Chief Kelly Sterna on April 18 for an assessment of County Councilor Randall Ryti’s house on North Mesa.
Know thy enemy: Embers and their pathways
It’s unlikely that houses in a typical residential neighborhood in Los Alamos would be overrun by a giant wall of flames. The more likely situation is that a large fire in the forest or canyons around town, and the accompanying winds, could potentially result in flaming debris being transported long distances, even several miles.
When these embers (or firebrands) fall on a bed of dry debris in the forest, they don’t make a sound, but the embers often help start new fires known as spot fires. In fact, just one ember blowing into town and landing in dry grass, a needle-filled roof gutter, or inside an attic after passing through an unprotected roof vent, could have serious consequences.
“We’re not going to see that 100-foot wall of fire come into town,” Sterna said. “It’s more about the ember cast from that main head of the fire getting pushed onto vegetation or up against the home, or trying to seek out those pathways that really get inside to start ignition.”
While this may seem implausible, experience from both the laboratory and the field shows these ember showers can have huge consequences.
The area around a structure can be divided up into three zones: zero to 5 feet from the structure (Zone 1); 5 to 30 feet (Zone 2); and 30 to 100 feet (Zone 3). The first two zones are, for most property owners in Los Alamos County, the most important from a risk management standpoint.
Zone 1: The structure and its immediate surroundings
“I know some folks get a little leery when I show up and they’re like, ‘Oh my God, you’re going to tell me to replace my whole house.’ I’m not, and I never would. It’s more of what can we do to really focus on the points around the home that are going to make the biggest difference,” Sterna said. “What we’re trying to eliminate are those pathways to where embers can get in, get stoked by wind, and then cause ignition.”
Good fire prevention begins with the roof. Metal panels or asphalt shingles are considered acceptable as long as they’re well maintained and structurally intact. Unsecured panels or peeling shingles can give embers a pathway to more flammable portions of a structure. Like ants, packrats, or a horde of hungry teenagers in your kitchen, once embers find a spot they like, there’s no telling what kind of damage will occur.
The same considerations should be made for siding. Stucco or brick is ideal, while untreated or deteriorating bare wood is not. The typical house also has many necessary openings on the exterior, such as crawl space and attic vents, exhaust fan ducts, or utility pipes. Any openings should be covered with at least 1/8-inch to 1/16-inch of mesh metal hardware cloth — commonly called chicken wire — that’s securely attached over the opening. Alternatively, fire- and ember-resistant vent covers can also be installed.
Zone 2: The yard
Councilor Ryti and his wife follow a landscaping strategy that’s fairly common among Los Alamos residences: trees and shrubs of varying types and sizes, areas of grass and ground cover, rockery, native plants, and raised beds. From a home insurance perspective, the area within 5 feet of the house should be free of any flammable material. However, from a fire prevention perspective, Chief Sterna doesn’t consider Ryti’s green groundcover as a serious pathway for fire.
A patch of short, dry grass ignited by a stray ember, even against a structure, is unlikely to release enough heat energy to cause further ignition. On the other hand, unmaintained dry grass or ground cover can have serious consequences for fire spread. The below video demonstration from Ada, Oklahoma, shows the effect of different levels of lawn maintenance on wooden fences.
Climbing the ladder
A more serious concern, particularly in more forested neighborhoods around Los Alamos, are built-up layers of dry pine needles or oak leaves. These dry and dense fuels, known as ladder fuels, are easily ignited by embers or ground fires and can provide an ideal incubator and pathway for fire spread and growth. These denser fuels act as kindling to generate more intense heat and can eventually contribute to the vertical ignition of more massive fuels, such as bushes and fences.
Pathway trees
Individual healthy trees are not inherently dangerous. In fact, many trees in our region, such as ponderosa pine, have evolved to survive low-intensity fires. Problems can arise, though, when a tree acts as a ladder by providing a pathway for fire to reach the eaves of a house, or if a heavy branch is weakened by fire or wind and it falls against a structure, giving embers a pathway to its more flammable innards.
In Zone 2, trees should be spaced with 10 feet between their point of closest approach. Small clumps of trees can be left in some areas but should be spaced farther apart. The base of the trees should be free of ladder fuels (tall grass or shrubs), and the lower branches of trees should be pruned up to shoulder height — approximately 5 feet, or 1/3 of the tree height — whichever is lower. These measures will allow a fire to travel around the base of the tree and reduce the risk of crown ignition.
Good fences make good neighbors, unless you burn the fence down
Wooden fences make excellent pathways for conducting fire through entire neighborhoods, a problem amplified by embers and heat generated by vegetation burning adjacent to the wooden fence.
Ideally, any fence material in contact with a structure should be made of fire-resistant — or even better, noncombustible — material. If fire threatens your property, opening the gates may create enough of a break in the fire’s path, particularly if a section of fence is adjacent to a structure.
Another vulnerability arises from flammable material — firewood, furniture and cushions, or a “just need to get to it” brush collection that so many of us have — stored next to or under structures, particularly if the fuel material is sheltered under decks and patios. Firewood piles should be stored at least 30 feet from a home.
Summary
It can be overwhelming to think about all of this, especially at this time of year, and especially for those of us who have experience with fires in years past. However, it’s not too late to take action, and even a little bit of work can go a long way.
Los Alamos has had the dubious honor of hosting the first “billion-dollar fire,” the 2000 Cerro Grande fire. It and subsequent fires have helped shape the concepts of developing “fire-adapted communities” — communities that, through planning and cooperation can survive, withstand, and recover from the ever-growing threat of wildfires.
What you can do to reduce the risk to your property:
Understand the principles: A good summary can be found in this Home Ignition Zone Guide from Colorado State University, and this guide to Home Hardening from the Living With Fire Partnership at University of Nevada, Reno.
Boomtown’s coverage of the March 5 Los Alamos community wildfire protection meeting can be found here.
Understand your individual risks: The Los Alamos Fire Department will evaluate your property from both a firefighting and home insurance perspective at no cost. Unfortunately, these assessments are in high demand, and LAFD will only take first-come, first-served reservations up to 14 days in advance. The confidential consultations usually take an hour or less. Any recommendations are shared only with the homeowner, and not with any third parties, like insurance companies or Los Alamos County code enforcement. Compliance with any recommendations is voluntary. Contact LAFD Wildland Division Chief Kelly Sterna, kelly.sterna@lacnm.us, for more information.
Los Alamos County is currently doing weekly brush bin collections through May 9. Residents can also sign up for bulk curbside pickups (up to 8 cubic yards of material) during the week of April 21 and May 5. The County’s eco station also provides on-demand bulk collection services for a $32.50 fee. Contact the Los Alamos Eco Station at solidwaste@lacnm.us.
Get your neighbors involved: “Once we get a neighborhood involved, that’s when we’re really making strides towards wildland fire hardness,” Sterna said. “Your neighborhood is only as hardened as the least-mitigated home in it.”
Let your friends and neighbors know if you can offer help, or if you need help.
Stay connected: Understand the “Ready Set Go” system. Los Alamos County residents should sign up for the “Code Red” alert system. And while Facebook is a popular communication tool in town, make sure you trust the source of the information.
And of course, stay tuned to Boomtown.