According to a new University of Colorado Boulder study published in Science Advances, wildfires are growing bigger and are burning more frequently in the United States.
The researchers studied records from around 28,000 fires starting in 1984 and ending in 2018. They used satellite imagery and state and federal fire history records to find that there were more fires in the past 13 years than in the previous two decades.
When they took a closer look at the most extreme wildfires in each region of the country, scientists found that in the West and the Great Plains, the average area burned per wildfire and the size of fire-prone areas increased everywhere across the U.S in the 2000s. The time and physical distance between new wildfires are shrinking. The blazes are also spreading into areas that didn’t burn before 2000.
In the West and East Coasts, fire frequency almost doubled. In the Great Plains, fire frequency quadrupled.
“Projected changes in climate, fuel, and ignitions suggest that we’ll see more and larger fires in the future,” said Virginia Iglesias, a research scientist with CU Boulder’s Earth Lab and lead author of the paper. “Our analyses show that those changes are already happening.”
So as more and more Americans prepare for wildfire season, here are a few tips and suggestions to keep your family and farm safe.
Get prepared for wildfire before it strikes.
According to Cal Fire, there are three ways your property can be exposed to wildfire:
- Direct flames from a wildfire or burning neighboring home
- Radiant heat from nearby burning plants or structures
- Flying embers which can destroy homes up to a mile away and are responsible for the destruction of most homes during a wildfire
You must prepare for wildfire and harden your home before the fire rages by installing fire ignition-resistant materials around your home and removing vegetation or debris from your roof, vents, windows, deck, and gutters where possible.
Taking the following measures to prepare your home can help increase its likelihood of survival when wildfire strikes.
Watch ‘Hardening your Home Against Wildfires’
The roof is the most vulnerable part of your home. Homes with wood or shingle roofs are at high risk of being destroyed during a wildfire.
- Build your roof or re-roof with materials such as composition, metal, clay or tile. Block any spaces between the roof decking and covering to prevent embers from catching.
- Remove accumulated vegetative debris from the roof.
Vents on homes create openings for flying embers.
- Cover all vent openings with 1/16-inch to 1/8-inch metal mesh. Do not use fiberglass or plastic mesh because they can melt and burn.
- Use Ember and flame-resistant vents (WUI vents).
Eaves and Soffits
Eaves should be boxed in (soffited-eave design) and protected with ignition-resistant* or noncombustible materials.
The heat from a wildfire can cause windows to break even before the home is on fire. This allows burning embers to enter and start fires inside. Single-paned and large windows are particularly vulnerable.
- Install dual-paned windows with one pane of tempered glass to reduce the chance of breakage in a fire.
- Consider limiting the size and number of windows that face large areas of vegetation.
- Install screens in all usable windows to increase ember resistance and decrease radiant heat exposure
Wood products, such as boards, panels, or shingles, are common siding materials. However, they are flammable and not good choices for fire-prone areas.
- Build or remodel your walls with ignition-resistant* building materials, such as stucco, fiber cement wall siding, fire retardant, treated wood, or other approved materials. This is especially important when neighboring homes are within 30 feet of the home.
- Be sure to extend materials from the foundation to the roof.
- Smaller spaces, such as the roof-to-wall area, should have their siding replaced with noncombustible material.
Surfaces within 10 feet of the building should be built with ignition-resistant*, non-combustible, or other approved materials.
- Create an ember-resistant zone around and under all decks and make sure that all combustible items are removed from underneath your deck.
- If a deck overhangs a slope, create and maintain a defensible space downslope from the deck to reduce the chances of flames reaching the underside of the deck.
Keep rain gutters clear or enclose rain gutters to prevent accumulation of plant debris.
- Install a corrosion-resistant and noncombustible metal drip edge for additional protection of the combustible components on your roof’s edge.
- Use a noncombustible gutter cover to prevent buildup of debris and vegetation in the gutter
Use the same ignition-resistant* materials for patio coverings as a roof.
Cover your chimney and stovepipe outlets with a non-flammable screen. Use metal screen material with openings no smaller than 3/8-inch and no larger than 1/2-inch to prevent embers from escaping and igniting a fire.
- Close the fireplace flue during fire season when the chimney is not being used.
Have a fire extinguisher and tools such as a shovel, rake, bucket, and hose available for fire emergencies.
- Add a battery back-up to the garage door motor so that the garage can easily be operated if power is out.
- Install weather stripping around and under the garage door to prevent embers from blowing in.
- Store all combustible and flammable liquids away from ignition sources.
- Treat windows and vents in the garage the same way as if it was a part of the house.
The best practice is to separate your fence from your house or upgrade the last 5-feet of the fence to a non-combustible material to reduce the chance of the fence bringing fire to your home.
Driveways and Access Roads
Driveways should be built and maintained in accordance with state and local codes to allow fire and emergency vehicles to reach your home. Consider maintaining access roads with a minimum of 10 feet of clearance on either side, allowing for two-way traffic.
- Ensure that all gates open inward and are wide enough to accommodate emergency equipment.
- Trim trees and shrubs overhanging the road to allow emergency vehicles to pass.
Make sure your address is visible from the road.
Use fire-smart landscaping to keep your property lean and green to help protect your family and home.
A fire-smart landscape is different than a well-maintained yard. In a fire-smart landscape, you use plants that don’t easily catch on fire and that can help stop the spread of fire to your home. These plants are often used in dry climates because they are also drought tolerant.
You don’t need a lot of money to make your landscape fire safe. A fire-safe landscape can increase your property value and conserve water while beautifying your home.
Watch ‘How to create Fire-Smart Landscaping w/ UC Marin Master Gardeners’
Be cautious of the claims of plants with a “fire-safe” label. Even though some plants are called “fire-safe” or “fire resistant”, they will all burn under the right conditions. The environment a plant grows in and how it is taken care of will have more of an effect on how flammable the plant is than what it is called. As a result, the fire-resistant rating of the proposed plant is less important than its features and the site where it will be installed.
Landscaping practices (or the pruning, maintenance, and cleanup) can have a greater impact on whether a plant ignites than does the type of plant it is. When bringing a fire-resistant framework to plant selection, consider whether the plant has a higher moisture content in the leaves (as these leaves will be less likely to ignite).
Create a defensible space around your home and buildings to help prevent the spread of fire.
To protect your home from a wildfire, you need to have defensible space. This is the area of land between your house and any wildland area around it. You want to make this space so that the fire will slow down or stop when it gets to your house. It is also important for firefighters because it gives them a safe place to work
Zone 0 – Ember-Resistant Zone
Zone 0 extends 5 feet from buildings, structures, decks, etc.
The ember-resistant zone is not required by law right now, but scientists have found that it is the most important of all the zones for fire safety. This zone includes the area under and around all decks attached to your house. It’s very important to keep this area clean so that fire or embers cannot start a fire on anything.
- Use hardscape like gravel, pavers, concrete and other non-combustible mulch materials. No combustible bark or mulch
- Remove all dead and dying weeds, grass, plants, shrubs, trees, branches and vegetative debris (leaves, needles, cones, bark, etc.); Check your roofs, gutters, decks, porches, stairways, etc.
- Remove all branches within 10 feet of any chimney or stovepipe outlet
- Limit plants in this area to low growing, nonwoody, properly watered and maintained plants
- Limit combustible items (outdoor furniture, planters, etc.) on top of decks
- Relocate firewood and lumber to Zone 2
- Replace combustible fencing, gates, and arbors attach to the home with noncombustible alternatives
- Consider relocating garbage and recycling containers outside this zone
Consider relocating boats, RVs, vehicles and other combustible items outside this zone
Zone 1 – Lean, Clean and Green Zone
Zone 1 extends 30 feet from buildings, structures, decks, etc. or to your property line, whichever is closer.
- Remove all dead plants, grass and weeds (vegetation).
- Remove dead or dry leaves and pine needles from your yard, roof and rain gutters.
- Remove branches that hang over your roof and keep dead branches 10 feet away from your chimney.
- Trim trees regularly to keep branches a minimum of 10 feet from other trees.
- Relocate wood piles to Zone 2.
- Remove or prune flammable plants and shrubs near windows.
- Remove vegetation and items that could catch fire from around and under decks, balconies and stairs.
- Create a separation between trees, shrubs and items that could catch fire, such as patio furniture, wood piles, swing sets, etc.
Zone 2 – Reduce Fuel Zone
Zone 2 extends from 30 feet to 100 feet out from buildings, structures, decks, etc. or to your property line, whichever is closer.
- Cut or mow annual grass down to a maximum height of 4 inches.
- Create horizontal space between shrubs and trees. (See diagram)
- Create vertical space between grass, shrubs and trees. (See diagram)
- Remove fallen leaves, needles, twigs, bark, cones, and small branches. However, they may be permitted to a depth of 3 inches.
- All exposed wood piles must have a minimum of 10 feet of clearance, down to bare mineral soil, in all directions.
Zone 1 and 2
- “Outbuildings” and Liquid Propane Gas (LPG) storage tanks shall have 10 feet of clearance to bare mineral soil and no flammable vegetation for an additional 10 feet around their exterior.
Many local government agencies have local ordinances for defensible space or weed abatement. These local ordinances will often be more stringent than the State’s minimum requirements listed above (e.g., San Diego County requires 50 feet clearance in Zone 1). Check with your local fire department or fire protection district for any additional defensible space or weed abatement ordinance requirements.
Plant and Tree Spacing
The spacing between grass, shrubs, and trees is crucial to reduce the spread of wildfires. The spacing needed is determined by the type and size of brush and trees, as well as the slope of the land. For example, a property on a steep slope with larger vegetation requires greater spacing between trees and shrubs than a level property that has small, sparse vegetation.
Remove all tree branches at least 6 feet from the ground.
Allow extra vertical space between shrubs and trees. A lack of vertical space can allow a fire to move from the ground to the brush to the treetops like a ladder. This leads to more intense fire closer to your home.
To determine the proper vertical spacing between shrubs and the lowest branches of trees, use the formula below.
Example: A five-foot shrub is growing near a tree. 3×5 = 15 feet of clearance needed between the top of the shrub and the lowest tree branch.
Horizontal spacing depends on the slope of the land and the height of the shrubs or trees. Check the chart below to determine the spacing distance
Taking the appropriate action in each of the risk zones can help improve the chances of your home surviving a fire. The website wildfirerisk.org details risk levels in communities across the country. Preventive measures are particularly important for those with the greatest exposure.