Want to see what it would take to destroy Payson?
Just ask Payson Fire Chief David Staub or Fuels Manager Kevin McCully to set up the Simtable and burn down Payson, again and again and again.
It’s all about the winds.
And the fuel moisture.
And the temperature.
Mix them in just the wrong proportion on the outskirts of Payson and you’ve got a town-destroying wildfire.
Amid perhaps the worst drought in 1,200 years, Payson faces a grim fire season. Fuels have dried to such a critical level that a March 8 fire in Tonto Basin fried 300 acres in a few hours.
Usually, fires that explosive don’t start until May.
Now, the Payson Fire Department has a tool to help show the danger — the Simtable. The fire simulator helps responders prepare for wildfires, floods, evacuations, storms and other emergencies as well as educate the public.
Moreover, the Simtable can help Staub and McCully pinpoint the most dangerous large overgrown plots of land sandwiched between housing tracts inside Payson. This will help them prioritize thinning and Firewising projects.
The Simtable provides a look into what can happen when conditions are like those that destroyed Paradise, Calif. — killing 85 residents unable to flee.
“The program has all the fuel types and terrain of the area,” said McCully as he worked to set up a table covered in crushed walnut shells. McCully can recreate the hills and valleys of an area with a brush of his hand.
The table then projects a map of Payson on the walnut shell surface, extending from all the way to Doll Baby Ranch in the wilderness beyond Main Street. Topography and wind patterns often create a path for fires to enter Payson from that direction. The drainage canyon used by the road to Doll Baby can easily funnel a wildfire into town.
Of course, many other areas also pose a danger. Last year’s Polles Fire due west of town for a time threatened both Payson and Pine.
The Simtable also helps firefighters understand what could happen if a fire starts on a patch of overgrown land inside town and spreads from house to house. Unfortunately, Rim Country fire departments lack the resources to stop fires in several structures at once.
If the conditions are just right, that situation might require evacuating the town.
90 degrees and 10% humidity.
Wind — variable.
Fuel moisture at 10%.
“Fuel moisture is an important component because it determines how flammable the fuel is,” said McCully. “Typically, June is the worst month for that.”
McCully set up the Simtable to illustrate how a fire would overwhelm Payson if it started in the Doll Baby area.
In the first example, McCully used a wind speed of 33 miles per hour coming from the southwest. In the next example, he used 59 mph.
Just a change in wind speed doubled the spread of the fire, even with the same fuel moisture, temperature and humidity. Pushed by a 59-mile-an-hour wind, the red lighting showing the spread of the fire in minute-by-minute intervals rushed up the road, bearing down on Payson.
The recent Pumpkin Fire near Tonto Basin underscored that lesson. The conditions on March 8 were perfect to spread a fire — low humidity, high winds and tinder-dry fuels. The fire exploded, forcing the evacuation of 140 residents. By March 9, a storm front increased the humidity and fuel moistures. If the fire had waited one more day, it would not have spread so quickly.
But the wall of fire on the “flaming front” isn’t the biggest danger for Payson, it’s the embers cast out ahead of the fire that pose the biggest problem.
“It’s the embers that come in and accumulate in gutters and the eaves of houses,” said McCully. “If enough embers accumulate, there will be fires.”
In most wildfires that take root in town, the embers account for most of the ignitions. That’s why the fire department is working on an overhaul of the town’s building code to require fire-hardening for new construction. Flagstaff and Prescott have already adopted such fire-adapted building codes. Homes built to the new codes cost little more to construct, but give the fire department precious time to deal with an ember storm before multiple buildings catch fire all at once.
Inside out fire
Staub used the Simtable to zoom in on a piece of land south of the high school and north of Frontier Street. It’s a tall hill that causes McLane Road to rise and then descend quickly.
If a fire starts at the base of the hill, it can easily run up the south-facing slope, then spread to nearby homes, said Staub.
“Anything from the southwest of town raises the heart rate,” he said.
He then reminisced about “three starts” that happened about the same time one year, one near the Jim Jones Shooting Range, another by the 7Up Ranch (southwest of town) and “one other came up over the hill” from Rye. Assists from other fire departments and a water tender from another agency got everything under control quickly, but it left an impression on Staub.
Staub used the same fuel moisture, temperature and humidity settings as McCully, but decreased the wind to 18 mph.
In his scenarios, he focused on the impact of Firewising — the removal of brush and branches close to homes and between properties.
In the first example, a fire escaped control within 22 minutes after starting on a property that hadn’t been Firewised. It quickly moved into the built up area from the brush.
Then Staub programmed the Simtable to show what would happen if the property owner had removed 40% of the fuel.
This time, it took 45 minutes to get to the same stage as the first scenario.
Staub said with the way the fire creeped through the brush, in 20 minutes of that fire he could have it surrounded with Rim Country fire resources. In comparison, by the time those same resources arrived at the first fire he programmed, they would have engulfed homes to try to control.
Already, the two fire officials have taken the Simtable out to the public.
“It’s interesting to see how people take it,” said McCully.
He’s seen some react in shock and fear.
“It makes an impact,” he said.