Wet monsoon storms gained strength across Arizona last week, largely bringing to a close a mild — but still frightening — fire season.
Fires burned dangerously close to Flagstaff, Tonto Basin and several smaller communities this year, most of them sparked by lightning in early July. The period of monsoon storms that yield lightning but little rain remains the most dangerous phase of Arizona’s increasingly volatile fire season.
The Woodbury Fire got loose and flashed across 124,000 acres, forcing the evacuation of some areas in Tonto Basin.
The Museum Fire burned just 2,000 acres on the outskirts of Flagstaff, but also caused evacuations — and continuing fears of devastating flooding as heavy monsoon rains hit still smoldering, denuded slopes.
Most of the rest of the fires that burned thousands of acres did more good than harm — thinning overgrown forests and clearing decades of accumulated dead and downed wood. Every fire at least reduces the risk of a subsequent, high-intensity crown fire in the same area. However, blazes like the 745-acre Blue River Fire in the burn scar of the Wallow Fire demonstrated how much fuel remains behind even after a forest-altering crown fire.
Moreover, the Museum Fire near Flagstaff could still lead to a billion-dollar flood if heavy monsoon rains hit the steep watershed overlooking Flagstaff.
Reservoirs also had a close call this year. The 4,000-acre Hart Fire burned close to the C.C. Cragin Reservoir and the 5,000-acre Newman Fire burned almost to Flagstaff’s Lake Mary Reservoir. Either fire could have drastically affected the reservoir if it had hit during the hot, dry months.
Moreover, the 7,500-acre Cellar Fire near Prescott roused haunting memories of the Yarnell Fire, which killed 19 firefighters.
Fortunately, the wet winter delayed the onset of the season. But then the late-arriving monsoon left the door to disaster propped open in the first half of July. Most of the fires were sparked by lightning during the “dry” monsoon storms before the rains finally arrived in late July.
So once again, the weather dictated the fire season. But here’s the thing: You can’t count on the weather these days, say the experts.
Arizona will likely see much more dangerous and erratic fire seasons, thanks to changes in the monsoon coupled with an increased risk of drought and rising temperatures. One recent study concluded monsoon patterns have changed dramatically in the past 400 years, with wild times ahead.
Researchers found a way to use growth rings on coral reefs to track the shifts in the monsoon patterns over the past 400 years, according to the study published in Nature Geoscience, a peer-reviewed scientific journal.
The growth of the corals reflected the warming and cooling of the surface waters that create El Nino and La Nina conditions. Those sea-surface warming affects weather all over the globe — including the intensity of the monsoon season in Arizona.
The research suggested that monsoons have grown more intense and unpredictable in recent decades, concluded the researchers from New South Wales and elsewhere. The coral growth rings closely matched the climate records from recent years, allowing the researcher to extend their models backward for centuries when climate records didn’t exist.
The research ultimately led to a tentative conclusion that monsoons will likely become more erratic as the climate gradually warms. That could mean more droughts, when the risk of megafires soars. But it could also mean more floods, which would greatly increase the potential damage from those fires.
And that’s bad news in a region that continues to struggle to deploy forest thinning and controlled burns to reduce the risk of ever-more frequent megafires.
It also suggests that forested communities like Payson, Pine, Show Low, Pinetop and Springerville will have to live with the threat of megafires for decades to come. Unfortunately, none of those communities have adopted the kinds of building codes and brush clearing policies that would prevent the whole town from catching fire like Paradise, California did last year – killing 88 people. Even the close approach of a wildfire could rain down so many embers that thickets of brush, overhanging eves and fire-prone roofs could spread a fire quickly through the community – even if the fire front’s a mile away.
Peter Aleshire covers county government and other topics for the Independent. He is the former editor of the Payson Roundup. Reach him at firstname.lastname@example.org