Bone dry fuels.
Yep. Critical fire weather.
And it’s just barely March.
OMG. This is scary.
The National Weather Service issued a “critical fire weather” warning for the end of this week across much of Arizona. The forecast calls for 10% to 15% humidity, 40 mph winds and extremely low fuel moisture.
The critical conditions hit the desert areas early in the week, with the fire warning spreading into the mountains at the end of the week — including much of New Mexico.
“A fire weather watch means that critical fire weather conditions are forecast to occur,” said a National Weather Service bulletin. Listen for later forecasts and possible red flag warnings. Dry fuels will be highly susceptible to ignition and spread. Mountain zones will be slower to reach critical RH due to cooler temperatures, though windy conditions still present the risk of fire spread.”
Fortunately, a Pacific storm will likely move through the region over the weekend, dampening the fire hazards. On Monday, Payson had a forecast high of 69 — well above normal. However, by Friday and Saturday we should see highs in the low 40s with lows in the upper 20s — with a chance of rain or even snow.
Still, the brush with critical fire conditions underscores the grim fire season forecast issued last week.
Payson has made some progress in preparing for what could turn into a record-breaking fire season, after two close calls last year — coming off a much wetter winter. The town has adopted a Firewise brush code to prevent embers from a nearby fire from spreading flames through the community. However, the move to reconsider the rejection by past councils of a fire-adapted building code has been moving slowly, as the pipeline fills up with new housing plans. Studies show that fire-hardened buildings don’t cost more to build, but do prevent fire from spreading easily from building to building in an ember storm.
The long-range weather forecast called for a dry March throughout Arizona, with high winds and unsettled conditions. Those dry, hot conditions will likely continue through May, according to the long-term forecast.
The June through August forecast also calls for above-normal temperatures, but offers a 50/50 chance of a normal monsoon, unlike last year’s “nonsoon.”
The long-range forecast states, “With drier and warmer than normal weather favored this spring, near-normal fire potential during the early part of this season will trend toward above normal fire threats as we enter the traditional fire season. Above normal fire threats look to develop at lower elevations (SE AZ into Yavapai County) by April, with above normal fire threat spreading north along the Mogollon Rim by May, then into all of Arizona by June.”
Almost the entire state remains in extreme or exceptional drought, after a dismayingly dry winter. At this time last year, all of southern Arizona including Gila County was basking in the first “normal” spring in years. The only stretch of “moderate to severe” drought was mostly confined to the sprawling Navajo Reservation in the northeast.
Once upon a time, the dangerous fire season didn’t start until late May and continued through June. This year, the fire season will likely start in late March and continue deep into July.
In a normal year, Payson gets 22 inches of rain, including 15 inches of snow. In March, that normally includes high temperatures that average 61 degrees and six days of rain totaling a little more than an inch.
At a time when streams should be brimming with snowmelt, the C.C. Cragin Reservoir remains at a low pool of about 20%, the East Verde’s flowing at about 6 cubic feet per second, Tonto Creek at about 12 cfs, White River at 48 cfs near Whiteriver. Roosevelt Lake has declined to about 80% of capacity, at a time of year when it should be filling with snowmelt.
NASA’s Global Climate Change website offered an analysis of 40,000 fires in the western United States between 1950 and 2017 and documented a steady increase in the size and number of wildfires.
The number of fires has grown by 61%. Moreover, the fires keep getting bigger — especially megafires that consume more than 100,000 acres. The records showed no megafires before 1970 and big increase since 2005. The records show that since 2001, we’ve had 17 of the 18 warmest years on record.
Nonetheless, since 1950, only 11% of lands in the West have burned — which means we still face a daunting backlog of land primed to burn. Meanwhile, an increasing number of fires are occurring in coniferous forests, including the ponderosa pine forests in northern Arizona.
Other research shows that the drought that has gripped much of the Southwest since 2000 ranks as perhaps the worst in the past 1,200 years, based on reconstructions of past climate trends from tree-ring studies and other lines of evidence.
The relatively normal 2019 briefly interrupted the emerging megadrought, expected to drive a vast array of changes, according to a study published last year in Science by researchers from Lamont-Doherty Earth Observatory at Columbia University in collaboration with researchers from other institutions, including the University of Arizona.
The researchers examined 1,600 tree-ring records and found four periods lasting more than 20 years with soil moisture content far below average. One megadrought in the 13th century lasted more than 90 years and may have contributed to the collapse of a network of ancient civilizations. That was longer lasting, but not as severe as the current drought.
Only one of the four megadroughts in the past 1,200 years compared to the severity of the current dry, hot spell. A drought in the late 1600s may have been slightly worse.
Drought in the Southwest remains deeply connected to sea surface temperatures in the Eastern Pacific — with cool La Niña ocean conditions shifting the jet stream and generally drying out the Southwest.
The researchers ran their results through 31 different computerized climate models and concluded that the gradual increase in global temperatures in the past century account for perhaps half of the severity of the current drought, along with the related big decrease in flows in the Colorado River.
So best take the brief dip into critical fire weather in March as a heads up to get ready for the start of a long, dangerous fire season in April.