Wildfires have gotten much larger in the West. Extended drought and abnormally dry weather have made desert vegetation much drier and easier to ignite. These conditions are now outpacing fire prevention efforts. That’s according to a recent study by the U.S. Forest Service and a group of Western universities.
In response, utilities like Salt River Project have dedicated lots of funds, as well as entire departments, to wildfire mitigation. As a water and energy provider, SRP wants to monitor power lines and watersheds in forested areas as closely and accurately as it can during fire season, but this requires a lot of manpower.
A pilot program with Albuquerque-based Growvera and Northern Arizona University’s School of Forestry could help change that.
On a hot summer day, SRP wildfire mitigation specialist Barry Johnson stood near a sagging mesquite tree in the Tonto National Forest. Though he was busy with the day’s installation, he still had to keep an eye on the Sycamore Fire that was burning in another part of this preserve.
He said the fire was moving dangerously close to one of SRP’s 500 kb power lines.
“We’re in heavy communication with our operations back home at SRP, as well as with the liaisons of that fire,” Johnson said. “So we’re able to kind of keep up communications and know what the current situation is on that fire, in order to change operations at SRP.”
“We want to try to keep the power on. That’s our job.”
Johnson reached for an auger, which he used to drill a 2-foot deep hole near the mesquite. Inside, four sensors designed by Growvera are installed at different depths. They will provide 15-minute updates on the amount of moisture in the soil.
The data will be shared with SRP and researchers like Salli Dymond, an NAU forestry professor and bonafide soil expert.
“I’ve been looking at soil moisture across the country, for — I don’t know — the past 15 years?” Dymond said. “So this is really exciting.”
“It gives us a lot of information on drought, how the trees are responding to drought, and what it means for wildfire risk across Arizona and the country.”
In addition to those in the soil, 30 more sensors are being attached to live and dead plants in the area, which will continuously monitor their moisture content as well.
Growvera CEO Brian Henderson says these insights will power wildfire forecasts in two ways. First, the soil probes will provide a water tension number for this section of the forest.
“That’s a bit scientific, but it’s mostly how much water is in the soil available for the plant to pull up from the soil to use to maintain its moisture content,” Henderson said.
That data will provide context for the plant moisture data, which is the primary metric firefighters use to predict how far and how high flames will grow in a forest.
“Wet plants don’t burn and very dry plants burn very aggressively,” said Henderson.
Growvera only recently discovered how its technology could advance fire forecasting. Until now, their sensors have mostly been used in precision agriculture.
Henderson says farmers have many reasons for wanting minute-by-minute crop moisture analysis.
“They want to closely monitor if plants are healthy, and they sometimes want to dry them out on purpose to enhance the flavor of, say, strawberries,” Henderson said. “Strawberries need to be dried out in order for them to develop their flavor, but you don’t want to reduce your yield.”
But according to Henderson, Matthew Hurteau, who studies climate change and forest ecosystems at the University of New Mexico, saw a different application.
“Hurteau said, ‘Hey do you think you could measure the water content of dead sticks on the ground in the forest?’” said Henderson. “That was about a year and a half ago, and we’ve run really hard now into this wildfire space and it's going really well. The data is very exciting.”
SRP says it's the first utility to use this form of technology in wildfire risk mitigation.
NAU, which is also participating in the pilot, is one of the premier universities for fire science and ecology studies. Dymond believes the sensors will help not only improve fire forecasting speed, but also accuracy.
“Soil moisture technology has come a long way in the past 15 years,” Dymond said. “We used to have to take a physical sample in order to measure that, and this sensor technology allows us to put sensors throughout the forest without the people power.”
"And rather than getting one point in time, we get 15-minute data, sometimes 5-minute data, 1-minute data, which is really informative for looking at how the system is responding.”
Wildfire forecasts rely on a combination of human-collected plant samples and open-air weather information such as wind conditions and humidity levels.
But fire scientists like Dymond wish they could keep a constant eye on the ground — and inside it — because that’s where fire risks really begin. Growvera's sensors will help her get one step closer to this.
“When the soil gets too dry below a point where the plants can physically pull it off the soil, that means the trees are going to be really, really stressed out,” Dymond said. “It means the fuels dry out, the leaves dry out, the branches dry out, and so there are really big implications for what this means for a fire igniting.”
Dymond says Arizona soils are prone to being dry, but the state has had some heavy monsoon seasons. This has challenged fire forecasting, because it makes it harder to predict plant and soil moisture without frequent sampling.
“These plants are adapted to a typical season where they’re used to dry periods,” Dymond said. “When we swing back and forth between wet soil, dry soil at different times of the year for these plants, we really don’t know how they’re going to respond.”
Johnson, who was leading the day’s installation, was a wildland firefighter for over 20 years before he joined SRP. He says the utility is among many in the West that have expanded its wildfire mitigation efforts.
He’s hopeful about SRP’s pioneering efforts with Growvera. The pilot currently spans six sites in the Tonto National Forest and Tonto Basin, as well as an area of Payson. If Dymond and her team confirm the data is accurate across these various terrains, the pilot should expand to other regions and partners.
“When you can find a company or a device that can give you that data every hour on the hour continuously,” Johnson said, “that just speaks for itself.”
-
In 2020, the Arizona monsoon season turned deadly when a powerful storm hit Apache Lake. The deluge took two lives that day: Deanna Peterson and Rick Le Grand. Ryan Schuster was there when it happened and is out now with a new book about the tragedy. -
The social media world of influencers promoting the great outdoors is vast. They camp, they hike — and they make it all look idyllic on Instagram. Lauren and Owen Steinwall certainly do all of that. But, they also are willing to show the not-so-glamorous side of the outdoors in Arizona. -
For the first time, the United States Forest Service authorized the use of N95 respirators for federal wildland firefighters. -
As wildfires are burning across the country, Flagstaff officials are looking to prevent catastrophic damage from happening here. How do they do it? By cutting down trees. A lot of them. -
Thompson says the closure is scheduled to continue through the end of September. The Pocket Fire has burned more than 27,000 acres.
