Fires’ fury unlikely to wane as dangerous conditions intensify

Fires’ furyunlikely to wane as dangerous conditions intensify

21 October 2007

USA — The skies over Southern California turneddark in the fall of 1970. A series of fires stretching from the San BernardinoMountains to the coast scorched more than 430,000 acres and destroyed nearly 700homes. It included the 51,800-acre Bear Fire in the San Bernardino Mountains,the largest ever in the Inland Empire.

More than three decades later, with better fire science and better tools athand, the scenario repeated itself, only this time it was worse. The fires of2003 ate up twice the acreage as in 1970 and incinerated 3,500 homes.

Get used to it.

Wildland fires keep getting bigger and experts don’t see an end to the trendany time soon. The entire western United States is affected, but SouthernCalifornia is a particularly volatile crucible where factors such as prolongeddrought, densely populated forests and longer fire seasons combine in the worstway.

“Californians are just going to have to learn to live with fire one wayor another,” says Matt Mathis, of the U.S. Forest Service. “The firesthat get bigger than 300 acres are getting a lot bigger than 300 acres.”

The San Bernardino Mountains have consistently hosted the Inland region’sbiggest fires. They were blackened in 1999 by the Willow Fire (64,000 acres) andagain in 2003 by the Old Fire (91,281 acres). That same week the Cedar Fire(273,246 acres) in San Diego County became the state’s largest on record.

In fact, of the top 10 largest fires in California’s recorded history, sevenhave taken place in the past 20 years. The most recent was this summer’s ZacaFire (240,000 acres) east of Santa Barbara.

Contributing to Troubles

Experts say several factors are involved.

Decades of fire suppression have left forests overgrown. In earlier times,such growth would have been limited by periodic low-grade fires. In recent years,efforts have been made to reduce the excess vegetation by letting remote firesburn and conducting controlled burns, but neither strategy is practical inSouthern California’s densely populated mountains.

Climate change has increased the length of the fire season, drying fuels outearlier, keeping them dry for longer and leading to fires of greater intensity.

The periodic drought cycle in which the region finds itself has exacerbatedthose conditions, as has a bark beetle infestation that’s killed millions oftrees.

With increasing numbers of homes bordering wildland areas, when a fire doesbreak out, more resources are focused on saving structures, making it harder tocontain other areas of the fire.

There is some disagreement as to the degree of importance of these factors,but most experts agree that each plays a part.

Richard Minnich is an earth sciences professor at UCR. He says environmentalfactors are much more important than the efforts of firefighters.

“We’re good at putting out little fires,” Minnich says. “Oncea fire is large, all that knowledge has trivial influence. We have no ability tocontrol large fires any more than we can control earthquakes.”

It wasn’t until a cold front moved in during the fires of 2003, bringing rainand snow, that firefighters were able to contain the blazes.

Battling Big Blazes

Minnich says few gains have been made in fighting large wildland fires.

“In practice, I don’t see any difference between now and 1950,” hesays, “except that you have bigger and bigger planes and the fires aregetting bigger.”

The problem he says, is the forest, which was once able to regulate itself,has an overabundance of vegetation.

“There is some historical evidence to support that Southern Californiaused to look like what we see presently in Baja (California),” says Minnich.

There, the chaparral environment supports fewer and more widely spaced trees.

Because of periodic natural fires, he says, the terrain is a checkerboard ofareas with varying degrees of vegetation. When a fire does start in an area withsufficient fuel, he says, it usually burns itself out once it reaches an areawith less vegetation.

This can take awhile. Historic data indicates that before the 20th century,fires in Southern California would sometimes burn for months beforeextinguishing themselves, Minnich says.

Back then, when there were few homes in the foothills and mountains, suchfires weren’t a problem.

But the San Bernardino National Forest is now home to 100,000 residents andis the country’s most densely populated forest. The presence of so many homeshas necessitated policies of fire suppression. Populated areas limit the abilityof fire managers to conduct controlled burns that would thin heavy fuels and,when fires do erupt, protecting those homes presents firefighters with greaterchallenges.

People, and the way they have changed the local landscape, are the greatestfactor in bigger fires, says Stephen Pyne, a professor of American studies atArizona State University and an expert in fire history.

“I think there is a tendency to attribute to global warming the increasein fires,” Pyne says. “It is a precondition, but it is not enough toexplain it.

“We know that we broke the cycle of (natural) fires by introducinglivestock and by removing American Indians who, the evidence suggests, burnedvery widely,” he adds.

Recent removal of more than 1 million trees killed by a bark beetleinfestation in the San Bernardino mountains have helped thin the vegetation. ButMinnich says it is not nearly enough.

“The people in Lake Arrowhead and Idyllwild need to start thinningseriously,” he says. “They need saw mills in both places.”

Lumber processing facilities are operating in the forest, but they

primarily deal with trees killed by the bark beetle. Minnich believescommercial lumber mills are needed to turn live trees into lumber.

Some experts argue that climate change is the primary driver in thephenomenon of larger fires.

Connie Millar studies climate and ecology for the U.S. Forest Service.

“I think the underlying feeling within the firefighting community (is)the growing realization of the increasing role of climate,” Millar says.

Climate Shifts

A study published last year in Science magazine connected earlier snowmeltand the later onset of winter weather to an increase in the size and intensityof fires.

“It was finally the coming out of the closet, as it were,” saysMillar. Before the study, she says, “The agency had been more in the modeof assuming land-use changes were the primary (factor).”

Tony Westerling, professor of environmental policy at UC Merced, co-authoredthe study with Tom Swetnam, a watershed management professor at the Universityof Arizona. Swetnam is scheduled to appear tonight in a “60 Minutes”story on global warming on CBS.

The two scientists looked at historical data on fires and climate.

They defined two periods, 1970-1986 and 1987-2003, and found the number offires in the second period was four times what it was in the first and asix-fold increase in the number of acres burned. The researchers also found thatsince 1986, the length of the active fire season — when fires are actuallyburning — increased by 78 days.

Finding Clearance

Neither Westerling nor Swetnam returned calls for comment, but Millar saysthe study shows there are no short-term answers.

“I think what we’re recognizing is this is a paddling-up-the-streambattle,” she says. “Do you get more paddles? What alternative is there?It’s not a satisfying answer for our generation.”

That’s because reducing the amount of greenhouse gases in the atmosphere willtake years.

In addition, as global temperatures warm and fires become more frequent, thecarbon gases released by fires add to the warming process.

All of these factors put the Inland Empire in a particularly perilous bind.The area’s ongoing drought, coupled with a longer fire season and the decreasein areas where controlled burns can be conducted safely, mean that the fire riskhere is only increasing.

About the only thing that those living in such areas can do is to make surethey have adequate clearance of fuels around their dwellings and communities. Inmany fire-prone areas, clearance is mandatory and is enforced by county and cityagencies. State law requires a 100-foot perimeter.

Glen Barley, unit forester for Cal Fire’s San Bernardino office, says since2003 fire personnel have been working to reduce fuels around mountaincommunities. He suspects, however, there are still many properties bordering thenational forest with too much burnable vegetation.

“There’s a significant percentage that are not meeting the treatmentthat would provide (the 100-foot buffer),” Barley says.

He notes clearance only does so much. Windborne embers can travel more than100 feet, he says, and homeowners need to make sure their homes havefire-resistant exteriors.

That’s because more and bigger fires are coming. It’s only a matter of time.

24. November 2017/by GFMCadmin