Hotter Summer Days Mean More Sierra Nevada Wildfires, Study Finds

The hottest days in the Sierra Nevada in California increase the risk of wildfires, and as the planet keeps warming the risks will increase even more.

The number of Sierra Nevada fires could increase by 20 percent or more by the year 2040, and the total burned area could increase by 25 percent or more, according to a research that examined daily temperatures and data from nearly 450 Sierra Nevada fires from 2001 to 2020 and projected the analysis into the future

The findings show how short events like heat waves impact fires. We were able to quantify that.

She said that the risk of fires is going to increase into the future because of the hotter days.

In the Western United States, there are more wildfires and they are growing longer. The Sierra Nevada experienced several large fires last summer, which has hurt California in recent years. The largest fire in the state's history was the Dixie Fire, which burned nearly a million acres.

Recent research suggests that global warming is a major reason for the increase in bigger and stronger fires.

There is an important difference between the findings of the new study and the earlier research. Most earlier studies looked at the monthly and annual data. Daily data was looked at in the new research.

The senior author of the paper and a UC Irvine professor of earth systems science said that they were trying to identify the role of individual temperature extremes on individual dates in the novel.

The researchers found that a 1 degree Celsius increase in summer temperature increased the risk of a fire by 19 to 22 percent, and increased the burned area by 22 percent.

An example of why hot weather can lead to more fires was given by Dr. Randerson.

If you accidentally create a spark and there is an ignition, you can stomp on it, or local fire agencies can come and put it out. The heat from the fire must evaporate before the vegetation can be seen. The spread of flames is slowed.

On a 100 degree day, the vegetation is so dry that a fire can grow quickly.

He said that a fire can last for weeks and weeks.

John Abatzoglou, who studies the influence of climate change on wildfires at the University of California, Merced, said the work adds to the growing scientific literature of climate-driven fire potential in forests of the West.

Dr. Abatzoglou said that the observed and projected upward march in temperatures is compounding pre-existing conditions, namely fuel accumulation in our forest, to escalate fire risk.

The data used by the researchers was averaged over the region and came from two sources: California's Department of Fire Protection and two NASA satellites.

After receiving her undergraduate degree in 2018, Ms. Gutierrez worked full time in Dr. Randerson's laboratory and had to wrangle a lot of data over many months.

She said it was worth it to research the link between extreme temperatures and fires.

We decided this is a question we need to ask. It is a bit tedious with the amount of data we are having to process, but it is an important question.