While studies warn that climate change has been found to increase the intensity and extent of wildfires across the Northwest, forestry experts and climate change observers say a potential connection remains hazy in Douglas County.
Stuart Liebowitz, a board member of the Douglas County Global Warming Coalition, said this doesn’t mean climate change is not happening in the western Cascades. It’s just more difficult to tell than in the eastern part of Oregon.
Climate change is a “threat multiplier,” meaning the threat of wildfires already exists through other factors, and the hotter, drier conditions that come with climate change make it worse. These other factors include a build up of hazardous fuels due to invasive species, outbreaks of diseases and insects, and fire prevention methods over the last 100 years that have kept fires from burning undergrowth regularly.
“The warning signs are all around, and we’re seeing this in the Pacific Northwest, and those signs don’t live in isolation,” Liebowitz said. “Being a timber-dependent community that really relies economically and health-wise on this resource, we need to pay attention to what’s going on around us rather than simply shrugging our shoulders and saying ‘it might not be happening here so let’s not worry.’”
The 2014 report from the U.S. Global Research Program lists the effects of climate change on Northwest forests.
“Climate change will alter Northwest forests by increasing wildfire risk and insect and tree disease outbreaks, and by forcing longer-term shifts in forest types and species,” reads the U.S. Global Change Research Program’s report, “Climate Change Impacts in the United States,” published in 2014, the most recent edition of the study.
The study states warmer and drier conditions have increased the amount of wildfires in the western U.S. since the 1970s and the trend is likely to continue, but some areas — like the western Cascades which encompass the Umpqua National Forest — may not show as much sensitivity to climate conditions as others.
“In the western Cascades, the year-to-year variability in area burned is difficult to attribute to climate conditions, while fire in the eastern Cascades and other specific vegetation zones is responsive to climate,” the study states in chapter 21: Northwest.
Daniel Leavell, an Oregon State University extension agent of forestry and fire science, said ingredients are in place for worse fire behavior on this side of the state.
“There are areas where there’s brush so thick it’s about 10 to 15 feet high and almost impossible to walk through. You add higher temperatures, lower humidity, wind and an ignition source to that mix and you have hot, severe fires that can spread over many acres,” Leavell said.
Not only has Leavell studied fire behavior since 1973, he has fought wildland fires every summer from 1978 to 2012 across the U.S. During that time, Leavell said he’s observed fires starting earlier and lasting longer with hotter and drier conditions extending past the end of fire season.
A red flag warning is issued if the temperature is more than 80 degrees, the moisture in the air is lower than 20 percent and the wind is at least 20 miles per hour.
“The link therefore, to climate change is the hotter the temperature, the drier the humidity, and when you add wind to the mix and an ignition source, fuel will burn,” Leavell said. “When the weather gets into red flag conditions the fuel with burn more intensely.”
Leavell said during the start of his career, daytime hours may have seen hot and dry conditions but the humidity would return at night, helping the fires to die down.
“But the trend I’ve observed personally is not only is it hotter and drier during the day, it’s hotter and drier during the night, and that humidity doesn’t recover as much as it did in the past,” Leavell said.
Kyle Reed, fire prevention specialist for the Douglas Forest Protective Association, said DFPA’s 105 years of records indicate there is no compelling evidence to suggest an increased amount of fires locally.
Reed said a DFPA record from 1951 portrayed very similar conditions to this year with above-normal rainfall and good snowpack going into fire season. It had rained normally until about March, when the rain stopped, the fuels dried out and created a busy year for fires with a total of 25,000 burned acres.
“We’ve seen this in the past just because things have been really wet and it looks like we’re going to have a good winter it doesn’t always turn out that way because everything just lines up perfectly,” Reed said. “When you have those really wet years you have the tendency to see a really good grass crop grow, but out in the wildlands where it’s not being utilized it creates a major fire hazard because eventually it does dry out.”
So far in 2017, 97 fires burned 16,873 acres on DFPA-protected lands, while the 10-year average was 95 fires burning 4,984 acres per year. The 50-year average was 99 fires burning 2,256 acres, and the average since 1912 was 104 fires burning 4,258 fires. The DFPA’s statistics are based on calendar years instead of fire seasons.
Reed said even though the past four years have proven to be active fire seasons, the number and acreage varies each year. In 2012 there were 68 fires burning 29 acres and 2010 had 42 fires burning 45 acres.
“Going into this fire season we had a wet winter and good snowpack, which was much different than previous years,” Reed said, adding southwest Oregon experienced a drought in 2014 and 2015, when DFPA saw an increased number of fire starts and acres burned. “For those years during the drought there was a considerable difference we noticed.”
The USDA Forest Service’s Quadrennial Fire Review for 2014 suggests across the Pacific Northwest, the U.S. Forest Service has reported longer fire seasons since the mid-1980s, starting about a month earlier and ending about a month later. The review predicts the fire season to extend to as many as 300 days per year in some parts of the country.
According to this review, since the 1980s, there are now 2.5 times more fires of 1,000 acres or more, 3.5 times more fires of 10,000 acres or more and 3.6 times more fires of 25,000 acres or more on U.S. Forest Service land across 12 western states.