Firefighters often talk about a fire triangle: Fire’s three essential ingredients are fuel, oxygen and heat. The western U.S. has potentially catastrophic levels of highly flammable fuel and plenty of oxygen. It is up to all of us to ensure that July 4 fireworks don’t provide the crucial third ingredient — heat.
In the U.S., 97 percent of wildfires near homes are caused by humans, with a huge spike on July 4. This year, the West is heading into the July 4 holiday in a state of extreme drought, with vegetation in some areas even drier than last year, when much of the region experienced its most severe wildfire season on record. The extremely dry landscape is poised for devastating wildfires, if July 4 fireworks, cookouts and other activities provide the spark.
Wildfire risk was elevated in the West even before the unprecedented heat of the past two weeks. The combination of record-low precipitation and extremely-warm temperatures over the preceding year, and an extremely rapid snowmelt this spring, stressed the vegetation. From that precarious starting condition, a series of heatwaves have dried the vegetation even further, punctuated by this week’s unprecedented — and truly exceptional — heat in the Pacific Northwest.
To get a feel for the amplification of wildfire risk from this week’s record-shattering heatwave, consider the town of Lytton in British Columbia. Lytton set Canada’s all-time temperature record of 121 degrees Fahrenheit on Tuesday, only to be destroyed by a fast-moving wildfire on
Wednesday, one of a number of fires that have erupted in British Columbia and the western U.S. following the heatwave.
While many large wildfires are not ignited by humans — including the large lightning complexes that set records in California last year — the vast majority of fires that threaten homes are. When fuels are dry and conditions are hot, it doesn’t take much. Some of the largest, most devastating fires in the West in recent years have been started by activities as mundane as a hammer striking a stake.
Fireworks are not just a source of sparks. They are ignition delivery systems, able to deliver sparks over wide and unpredictable areas. The best way to limit ignitions from fireworks is to refrain from celebrating the holiday with illegal fireworks. Illegal fireworks are a massive problem. This week the California Department of Forestry & Fire Protection (“CAL FIRE”) announced that it has seized almost 300,000 pounds of illegal fireworks in the past year, including almost 80,000 pounds in 2021.
For July 4, we have many opportunities to enjoy safe, legal firework shows. But this year especially, we should use the gaps between “oohs” and “aahs” to think about other things we can do to decrease wildfire risk. Unfortunately, fireworks are just one risk factor. Other factors, including where we live, how we have managed fuels and, especially, climate change are quickly making our normal routines, resource use and risk management strategies ill-suited for the current landscape.
The annual area burned in the West has increased sharply in the past four decades (about 10-fold in forested areas). Warming, through its effect on vegetation dryness has doubled the forest area burned since 1984. Over that period, the frequency of extreme wildfire weather in California has more than doubled, with increased temperature and decreased precipitation extending the period of hot, dry conditions later in the year, when strong off-shore winds normally blow.
These long-term changes have been felt acutely in the region in recent years. The seven largest wildfires in California’s history all occurred since 2017, including five in 2020, when large, highly destructive fires also ravaged Colorado, Oregon and Washington, and millions of people were impacted by widespread smoke.
While every large wildfire results from a confluence of different conditions shaped by ignition source, vegetation conditions, weather, human exposure and vulnerability, and available firefighting resources, we are now in a climate where the conditions that create very large, destructive fires are much more likely. And the conditions in 2021 are particularly ominous — with record-setting heatwaves on top of a deep, widespread drought.
The good news is that there are opportunities to reduce the risks right now. The very early elevation of the national preparedness level by the National Interagency Fire Center highlights the need for additional firefighting resources. This week, President Biden convened governors of western states to discuss options for federal and state governments, including increasing pay for underpaid and over-stretched federal firefighters. There are also many actions that communities, individuals and companies can take to reduce fire risk through management of vegetation, home hardening, clearing defensible space around buildings and — though the prospect is not pleasant — Public Power Safety Shutoffs to avoid catastrophic fires caused by the electrical grid.
We have a unique opportunity to start taking action this weekend, by working to keep July 4 from living up to its historical distinction as the single biggest day of the year for human ignitions. Avoiding illegal fireworks could literally mean the difference between life and death.
Noah S. Diffenbaugh is the Kara J Foundation professor and Kimmelman Family senior fellow at Stanford University.
Christopher B. Field is the Perry L. McCarty director of the Stanford Woods Institute for the Environment and the Melvin and Joan Lane professor for Interdisciplinary Environmental Studies at Stanford University.