It’s already started.
Firefighters contained the first big wildfire of the season last week — a 1,000-acre grassland fire near Concho in Apache County.
Despite two late-breaking winter storms, the region has suffered a dry winter, and the forecast calls for a warm, dry spring with an early start to the fire season.
The Ranch Fire started about 4.5 miles southwest of Concho and winds quickly drove the fire to 1,000 acres.
“Folks, please pay attention to weather conditions when working outdoors. Do not burn or use equipment that throws sparks when it’s windy,” the Arizona Department of Forestry said on Facebook.
The National Weather Service forecast for the fire season concludes, “an up and down pattern overall through the spring, with generally dry conditions resulting in an earlier than normal start to a large fire season.”
The March fire season forecast issued this week concluded, “Above normal significant wildland fire potential will begin in southeast Arizona in March, with the above normal significant wildland fire potential anticipated to spread northwest into central Arizona by April. Above normal significant wildland fire potential should develop in the Four Corners region by May, with the above normal significant wildland fire potential gradually spreading northwest into Yavapai County by June. For the time being, near normal significant wildland fire potential is expected along the Mogollon Rim this fire season.”
We’re in better shape than the same time last year, when almost the entire state languished in severe drought. This year, most of the state’s “abnormally dry.”
The news lends urgency to the efforts to reduce wildfire risk through an acceleration of thinning projects augmented by managed fires.
Recent studies suggest that thinning projects and managed fires can significantly increase runoff into streams and reservoirs. So do uncontrolled wildfires — but those flows often turn into floods, which damage vital riparian areas and fill reservoirs with debris.
For instance, wildfires increased runoff by about 30% on watersheds near the Mogollon Rim that have burned since 1984, according to a study published in the Proceedings of the National Academy of Sciences. The increased streamflow fades away after about six years as new vegetation fills in. The finding underscores the need to follow up thinning projects or controlled burns with additional prescribed fires after five or 10 years to maintain the benefit — and keep the risk of far more damaging megafires from again building up.
Another study found that the emission of water vapor from trees in California’s Sierra Nevada has decreased significantly in the past 30 years due to the combined effects of wildfires, thinning projects and controlled burns.
The water saved totaled some 3.7 billion gallons annually in the Kings River Basin and 17 billion gallons annually in the American River Basin. The water remained in the soil or flowed into the rivers rather than evaporating through the leaves of trees, according to the study by researchers from the National Science Foundation and the Southern Sierra Critical Zone Observatory published in the journal Echohydrology.
The researchers said a century of fire suppression has dramatically changed the structure of the forests in the Sierra Nevadas, creating a forest smothered in small trees that built up with the elimination of the natural fire regime, with low intensity fires every five years or so. The same thing has happened in Arizona, studies show. Thinning projects and wildfires both reduce the number of trees per acre — leaving more water in the soil and in streams. However, the researchers noted that high intensity fires that sear the soil and kill almost all the trees may also increase runoff, but they also produce devastating floods and debris flows.
The researchers estimated that forest thinning and prescribed burns could increase runoff into streams and reservoirs by 10%, while reducing the odds of damaging flooding and town-destroying megafires.
“We’ve known for some time that managed forest fires are the only way to restore the majority of overstocked western forests and reduce the risk of catastrophic fires,” said James Roche, a National Park Service hydrologist and lead author of the new study. “We can now add the potential benefit of increased water yield from these watersheds.”
The studies suggest the drought and the growing water shortage may provide a strong incentive to thin Arizona’s northern forests to augment the Valley’s increasingly overstretched water supply. Arizona recorded the second highest growth rate of any state during the pandemic even as the drought tightens its grip.
And that in turn suggests forested communities will have to adapt to managed fires and controlled burns every five or 10 years.
Of course — that’s the long-term challenge.
As the Ranch Fire showed, we’re already headed into another potentially dangerous fire season — months ahead of the fire season that once started in May or June, before the drought, an overstocked forest and a steady rise in average global temperatures changed wildfire risks throughout the state.