FRISCO —Western wildfires have always been shape-shifting beasts, roaring to life wherever there is hot and dry weather, wind and fuel. But a cool and wet Colorado summer brought at least temporary relief from recent years, when smoky skies and spiraling wildfire disasters spread across the state from the San Juans to the northern Front Range.
Through early November, the state saw just 803 wildfires that burned across 29,400 acres, the smallest wildfire footprint since 2007. Excluding a fast-burning, late-July 21,000-acre grass fire in the sparsely populated northwestern corner of the state, wildfires have burned on just 8,000 acres this year, a fraction of the acreage during recent seasons.
By contrast, in 2013, wildfires in Colorado burned across 195,000 acres, including the 14,280-acre Black Forest Fire in June, second-costliest in state history, and the 110,405-acre West Fork Fire complex, the state’s second-largest wildfire ever, behind the 2002 Hayman Fire.
2012 – 246,000 acres
2011 – 161,000 acres
2010 – 44,000 acres
2009 – 50,456 acres
2008 – 141,964 acres
2007 – 20,739 acres
2006 – 94,483 acres
2005 – 27,390 acres
2004 – 24,996 acres
This year’s to-date wildfire acreage for the entire Rocky Mountain region of the Forest Service (Wyoming, Colorado, Nebraska, North Dakota, South Dakota) is less than 70,000 acres, less than last year’s total in Colorado alone.
The respite in wildfire activity in the Southern Rockies came as a relief to edgy Coloradans, who have been watching huge tracts of forests burn each year since 2002, the year of the Hayman Fire. Through early November, Colorado wildfires have burned across 29,400 acres, the smallest wildfire footprint since 2007.
National numbers below average
This year’s Colorado wildfire season reflects the national numbers. For the year to date, the National Interagency Fire Center has reported 47,579 fires around the country, the lowest number going back to the beginning of formal records in 1960. So far this, fires have scorched about 4.3 million acres nationwide, well below the running 10-year average of about 7 million acres per year.
The relative calm this year enabled the U.S. Forest Service and its state and local partners to speed up forest-thinning and brush-clearing work aimed at reducing wildfire risks. Across the agency’s Rocky Mountain region, the Forest Service treated 121,030 acres in 2014, including 37,020 acres in Colorado.
In some other recent years, ballooning firefighting costs forced the Forest Service to raid other budget categories, in some cases halting proactive forest treatments.
Fire experts and scientists caution against reading too much into year-to-year comparisons. The best way to understand the potential threat of wildfires is with a nuanced view, cognizant of the many different ingredients in the wildfire recipe.
This year’s decline in wildfires shouldn’t be seen as a long-term downturn, but more of a weather-induced temporary lull, said Tania Schoennagel, a wildfire expert with the University of Colorado’s Institute of Arctic and Alpine Research. Weather during the fire season is all-important. Even a forest filled with beetle-killed trees and dry brush can’t burn if it’s wet, Schoennagel said.
Firefighters and forest managers won’t let down their guard based on what is probably a statistical blip. Across the country, about 65 million acres of national forest lands remain at risk from big wildfires because of fuel buildups, insect infestations, non-native plant invasions, drought, and climate change.
In fact, wildfires could get even bigger in coming years if droughts and heat-waves increase as projected by most climate models. Under the right conditions, wildfires could double dramatically from the current average, to 12 million to 15 million acres annually, Forest Service Chief Tom Tidwell warned Congress earlier this year.
Size isn’t everything
Making year-to-year comparisons can be somewhat misleading, especially when it comes to measuring impacts to communities, said Ed Delgado, head of predictive service for the Boise-based National Interagency Fire Center.
Large fires are sure to return to the Southern Rockies in the years ahead, and the best way to understand what drives the cycles is with a nuanced, science-based view that considers all the factors, Delgado said.
“You might have a big fire year, related to just a couple of individual fires, but they might not have big impacts on large communities of people,” Delgado said. “Sometimes fire size isn’t always the biggest thing. A 300,000 acre fire may not have the same impact as a 15,000-acre wildfire,” he said, singling out last year’s Black Forest fire as an example of an extremely destructive blaze that wasn’t all that big by 21st century standards.
But the general upturn in fire activity since about 2000 is obvious and well-documented, Delgado said.
“Every year, some areas have been seeing their largest fires ever. Colorado 2 years in a row, New Mexico and Arizona, where the 2011 Wallow Fire burned across more than half a million acres, 841 square miles,” he said. “You have to put it all into perspective. There are a lot of reasons you have the really big record-breaking fires, but it’s hard to put your finger on any one reason.”
Delgado said there’s a lot of talk about climate versus the weather when it comes to fire, but emphasized it’s the actual weather event when the fire starts that “determines how big, how fast the fire will grow.”
In the southern Rockies, including Colorado, it takes sustained hot and dry weather, which enables the fire season to build upon itself, Delgado said.
“This year, you’d get a few days of really hot weather with fire starts, then a cool wet period would put the fire out. The fire season was episodic this year,” he said.
It’s also important to consider how the weather of recent years can be a factor, he said. This past summer’s moisture suppressed wildfires but also nurtured a crop of grasses that is a prime fuel for future fires.
Showing just how subtle fire cycles can be, Delgado said the grass is less of a future factor if it’s heavily matted down by snow during the winter. But if it stands tall through a dry and windy winter and spring, it will quickly carry hot flames to find pockets of heavier fuel.
Delgado said the link between temperatures and wildfires is clear. Warmer weather drives the relative humidity down.
“When you get below the 20 percent range, that’s when you see the vast majority of fires. The finer fuels lose their moisture, and that’s what carries fire and sustains the heat availability to ignite larger fuels and timber,” he said.
Fire scientists may not be able to predict wildfire hotspots from year to year, but gaining an understanding of long-term trends can help communities prepare in places like Colorado, where continued housing development along forest fringes is putting people in harm’s way — with implicit knowledge that the wildfire risk will increase in the next few decades.
The Red Zone, more formally known as the wildland-urban interface, has expanded by 60 percent since 1970, mainly in forests where moderate- to high-severity fires are part of the ecological landscape. Only 16 percent of the wildland-urban interface in the western U.S. currently is developed (20 percent in Colorado) but those numbers are rising, according to the nonprofit research group Headwaters Economics, which is based in Bozeman, Montana.
At the same time, we know that:
– Large wildfire activity started growing suddenly and rapidly in the mid-1980s, with higher large wildfire frequency, longer wildfire durations, and longer wildfire seasons.
– Since 1986, the number of large forest fires has quadrupled and the total areas burned by these by these fires was more than six and a half times its previous level.
– Since 1960 (as far back as reliable records go), the three years with the largest number of acres burned on all lands have all occurred since 2006 (2006 – 9.8 million acres burned; 2007 – 9.3 million acres burned; 2012 – 9.3 million acres burned).
– The number of wildfires exceeding 50,000 acres has increased over the past 30 years, with most of that change occurring over the past 10 years.
Given the certainty of more Colorado wildfires, a new emphasis on land use planning is needed to reduce the risks to towns and neighborhoods, Schoennagel said. Current policies focused on aggressive firefighting and preventive forest treatments may actually be encouraging developments on “inherently hazardous landscapes, leading to an amplification of human losses to wildfire” she concluded in a recent study on wildfire patterns and exurban development.
[Image: A photo taken from the International Space Station shows thick smoke from the June 2013 West Fork fire complex in the Colorado San Juan Mountains. Photo courtesy NASA Earth Observatory]