Record average wildfire size to be set during nation’s ongoing 2020 wildfire season

With wildfires nationally now averaging about 168 acres each, the 2020 wildfire season is on track to break the previous record of 145 acres, set in 2018.

Data from the National Interagency Fire Center shows that while the number of wildfires each year has been decreasing, the size of the fires across the continental United States has been increasing.

California alone saw well over 4 million acres burn across the state, with five of the 20 largest wildfires in the state’s history taking place this year. Fire season is not yet over, with new blazes like the Bond Fire breaking out in Southern California earlier this week during red flag warning weather conditions.

Through Nov. 29, nearly 9,485 wildfires have occurred in 2020, Cal Fire says, a combination of state of federal numbers. That averages to 440 acres per fire. Two years ago, the average was 221 acres per fire.

While there is variety in the size of fires from year to year, the average has been increasing significantly over time, with the average between 1985 and 1990 reaching only 31 acres.

The massive growth is largely attributed to global warming and the dry fuel conditions it creates. In California, the dry conditions are still apparent, with many regions in the state still without any significant rainfall this year.

“We can still see these large, devastating wildfires. We saw four of them spark just over the past couple days down in Southern California during the Santa Ana wind event. The potential is definitely still there,” said Lynne Tolmachoff, a spokeswoman for Cal Fire.

Hotter temperatures and long droughts have created fire seasons that get longer each decade, Tolmachoff said. Over the past 30 years, fire season has been extended by about 70 days, reaching into late fall. The heat of summer dries vegetation out, becoming fuel for flames and allowing for rapid fire growth.

For the 2020 wildfire season, other natural events, including lightning strikes, created unexpected weather events that led to rapid growth of the flames.

The decrease in the number of fires is due to numerous small factors, according to Tolmachoff. Increased awareness of wildfire prevention has contributed to more restrictions over the years on burn piles, limiting the size of the pile and the days during which the fires can be started.

The National Fire Protection Association has also reported that highway vehicle fires have been reduced from 456,000 in 1980 to 182,000 in 2018, largely due to more safety measures within cars. Tolmachoff said that now it is much more unlikely that parts from a catalytic converter will come off of a car and spark a wildfire.

Anti-smoking campaigns have also contributed to a lower number of cigarette-related fires, with fewer incidents of fires being started after a lit cigarette is thrown out a window. The development of self-extinguishing cigarettes that burn out when left lit also has helped.

Climate change and California wildfires

Wildfires have always been part of life in California. The past four years have brought some of the most destructive and deadliest wildfires in the state’s modern history.

Nearly 180 people have lost their lives since 2017. More than 41,000 structures have been destroyed and nearly 7 million acres have burned. That’s roughly the size of Massachusetts.

So far this year, 30 people have died, according to Cal Fire.

Meanwhile, this year’s August was the hottest on record in California. A rare series of lightning storms sparked a series of fires, including the August Complex that has burned nearly 1 million acres, making it by far the largest wildfire in California’s recorded history.

The 2017 wildfire season occurred during the second-hottest year on record in California and included a devastating string of fires in October that killed 44 people and destroyed nearly 9,000 buildings in Napa, Lake, Sonoma, Mendocino, Butte and Solano counties.

The following year was the most destructive and deadliest for wildfires in the state’s history. It included the Camp Fire, which destroyed the town of Paradise and killed 85 people, and the enormous Mendocino Complex.

This story was originally published December 4, 2020 at 9:38 AM.