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Dry fall fuels wildfires from coast to coast, raising concerns in Arizona

Harry November 15, 2024

Weeks without rain, higher-than-normal temperatures and piles of dry fuel scattered on the ground have led to red-flag fire risk warnings.

While not a typical decline forecast in the northeastern United States, drought conditions and human-caused fires have led to unusual fire activity.

Wildfires in New York, New Jersey and surrounding states, as well as wind-induced burns in California, concern scientists and wildland managers across the country.

“We are accustomed to long dry spells in the Southwest because of seasonality and precipitation,” said Michael Crimmins, a climate scientist at the University of Arizona.

“But when it doesn’t rain in the eastern part of the country, which is used to rain every few days, you can quickly enter drought conditions.”

A series of wildfires have flared across the Northeast, from a small burn in Brooklyn’s Prospect Park to the 5,000-acre Jennings Creek fire on the New York-New Jersey border that killed an 18-year-old park ranger.

On the other side of the country, the Mountain Fire in California’s Ventura County destroyed nearly 250 structures and burned more than 20,000 acres this week.

After a record-breaking decline with extreme heat and drought conditions, fire risk continues beyond traditional peaks during wildfire season.

Here’s what’s fueling fall fires, what the current fire risk is in Arizona, and how climate change is affecting the lengthening of the fire season.

What fuels autumn fires?

Summer heat and drought continued into fall across much of the United States this year, setting the stage for late-season fire activity on both coasts.

“October was one of the driest Octobers on record for the continental United States, and added to the heat,” Crimmins said. “The heat gripped much of the country during that period.”

In dry conditions and above-average temperatures, evapotranspiration, which is the transfer of water from plants and soil to the atmosphere, increases and dries out the soil, Crimmins said.

Authorities issued red flag fire warnings from New Jersey to Massachusetts after weeks of little rain in the Northeast.

Connecticut has reported more than 80 brush fires and is under a Phase 2 drought advisory. Massachusetts saw a 1,200% increase in fire activity in October, reporting more than 200 wildfires compared to the average of 15 fires.

The Jennings Creek Fire in New York and New Jersey is out of control, and officials are concerned that strong winds could expand the blaze.

Although fall brings cooler temperatures, it can also summon more fuel: leaves.

“The trees were defoliated and some fuel was spilled on the ground,” Crimmins said. “I’ve seen firefighters use leaf blowers as part of their firefighting equipment, blowing leaves to clear fire barriers because that’s what moves material on the ground.”

Wildfires are not unheard of in the Northeast, but this fall has seen a sharp increase in fires along with rapid growth.

Fires are more common in California, but activity this time of year is always cause for concern; Santa Ana winds are a seasonal wind pattern that occurs most frequently in the fall, bringing extremely strong, dry winds and lower relative humidity. via Southern California. Winds come from the desert and move towards the coast.

“Any human ignition that occurs downwind will also be reflected in the large, devastating fires occurring in Southern California,” Crimmins said. “Like us, Southern California has had a really wet winter and has all kinds of plants growing ready to burn.”

Wildfire season in Southern California continues later in the year than in other parts of the country, due to winds that can turn sparks into infernos.

What is the fire risk in Arizona?

Fire activity in the Southwest generally peaks in April, May and June, but the region depends on moisture from monsoon rainfall for fire activity to subside. This year’s monsoons were sporadic and were the seventh driest monsoon on record.

“It’s all about moisture,” said Tonto National Forest fire marshal Andrew Mandell, noting the dry conditions in the forest. “We’ve had some moisture and there’s a chance of some moisture in the near forecast.”

While the higher parts of Arizona are starting to be covered with snow, there is still a risk of fire in the lower areas.

Mandell said it was an “extremely busy” fire season for the forest, with 195 fires burning 130,000 acres. Although the fire risk has decreased, fires are still possible in Tonto. Tonto forest covers low-elevation wilderness areas where snow is rare.

“We continue to have fires, we had an 80-acre fire in the Mesa Ranger District (Tuesday),” he said. “They’re not getting out of control, but we’re still seeing fires grow quite a bit into November; with a longer fire season like we’ve seen in Tonto, this becomes more common.”

Extreme risk fire restrictions were not implemented throughout the Tonto National Forest until early September, and fire crews began prescribed burn operations late due to poor conditions.

This week they began prescription burn operations on the Globe Ranger District.

However, as the risk decreases, this does not mean that there will be no fire.

“We absolutely want everyone to enjoy public lands responsibly, whether there are fire restrictions or not,” Mandell said. “Be careful and responsible with fire at entertainment events, because we definitely do not want unwanted fires to spread into nature.”

How is climate change affected?

Although wildfires are a natural event that can provide modest benefits to ecosystems, scientists are concerned about the lengthening of fire seasons and large-scale fires. They believe climate change is playing a role in worsening fires.

“Climate change is a part of everything, but it’s not the root cause of one thing,” Crimmins said. “This is kind of like the background situation.”

It’s still unclear how the warming atmosphere affects individual weather events like Santa Ana winds or fall precipitation, but scientists know that higher temperatures dry out vegetation more quickly, creating dangerous fuels.

This year is set to be the hottest year on record, with drought conditions across much of the country and fire season continuing to extend.

“Since the beginning of my career, we’ve seen fire seasons get longer over time — and I think I’m 30 years into this — they’re definitely longer than they used to be,” Mandell said.

According to Crimmins, fire activity in the Northeast is something scientists and fire crews need to pay attention to.

“It’s a strange combination of things, and while it’s not unprecedented, it’s quite unusual to have long dry spells alongside rising temperatures. “This just increases the risk of fire,” Crimmins said. “This is weird and we need to pay attention to these things.”

Hayleigh Evans writes about extreme weather and related topics for the Arizona Republic and azcentral.com. Email him story tips: [email protected].