Climate change contributes to greater frequency, intensity, and severity of wildfires by increasing the likelihood of extreme “fire weather,” meaning climate and weather conditions conducive to fire ignition and spread. Fire weather is characterized by a combination of low humidity, high temperature, and strong winds.
Every fire starts with a source of ignition — an incident or action that causes a spark. Lightning is one common cause of fire; even just heat from the sun can cause fire under the right circumstances. But often, it’s human activity that serves as a source of ignition. In fact, in the United States, roughly 85 percent of wildfire ignition sources are human-caused according to the U.S. Forest Service.
ClimateCheck’s wildfire risk assessment incorporates fire weather projection, ignition probability, and information about landscape characteristics. With regard to landscape, we look at data on vegetation that could potentially serve as fuel for fires, land use such as proximity of buildings, and topography.
During summer, two common activities can act as ignition sources for fire: Campfires and setting off fireworks. These activities can be especially dangerous in regions that are particularly vulnerable to wildfire, such as the western United States.
Campfire and fireworks safety tips
Before building a campfire or setting off fireworks, check local rules and regulations to ensure the activity is permitted in your location. You may be required to acquire a permit for certain activities. If you do engage in these summer activities, take precautions.
Among human-started wildfires on U.S. Forest Service land, campfires are the leading cause. If you build a campfire, it’s important to follow precautions.
- Check local rules and regulations. Do not start a campfire if prohibited in your area or if there is a seasonal fire restriction.
- Choose a location far away from potential fuels like brush, decaying leaves or logs. Move potential fuels out of the fire’s periphery.
- Don’t build a bigger fire than you need.
- Have a shovel and bucket of water nearby in case you need to quickly extinguish the fire with water or dirt.
- Do not leave the fire unattended.
- Put the fire out completely before sleeping or leaving the location unattended.
Not only are fireworks dangerous, but they caused more than $3 million in property damage in California in 2021. Some states and localities ban fireworks, and many set strict restrictions on what kinds of fireworks consumers may purchase and when you can set them off. Here are some precautions to take if you plan to use fireworks on July 4th or at other times.
- Check state laws and local ordinances for rules about fireworks in your area.
- Don’t set off fireworks near vegetation or building structures. Look for a safe location, such as a parking lot.
- Have lots of water or a hose on hand to put out fireworks if needed.
- Designate a sober adult to set off the fireworks.
- Never point fireworks at a person or piece of property.
- When you’re done setting off fireworks, douse the remains in water for 15 minutes, then wrap them in plastic before disposing. This ensures that they stay damp, preventing them from catching fire again.
Learn more about fireworks safety.
How does ClimateCheck model fire risk?
ClimateCheck wildfire risk estimates incorporate future likelihood of fire weather under different emissions scenarios, land cover/land use data, and probability of ignition.
- MACA CMIP5 Statistically Downscaled Climate Projections: This model is used for extreme wet bulb heat and wildfire projections. It is statistically downscaled by one of our advisors, Dr. John Abatzoglou, a climatology professor at UC Merced. You can find more information about MACA here.
- U.S. Forest Service Research Data Archive, Wildfire Risk to Communities Data: We use this data to help provide us with a picture of current wildfire risk based on land cover/land use and ignition observations to produce burn probability and flame length estimates. You can learn more about this data here.
- USGS digital elevation model (DEM): A DEM provides a topographic, stripped-down representation of the earth, and is created from an array of sources. You can read more about the USGS DEM here.
- Multi-Resolution Land Characteristics (MRLC) National Land Cover Database (NLCD): This database comes from the MRLC consortium, a group of federal agencies that create and organize granular land cover and land use information for various environmental and modeling purposes.