Firefighters Bound by Weather’s Whims

Fighting forest fires combines war strategies such as pincerlike movements, the modern technology of global positioning satellites and old-fashioned toil with shovels and picks. Ping-Pong balls come in handy too.

“We use every tool in our toolbox,” said Greg Gilpin, a 30-year forest fire veteran who’s commanding the 2,800 troops battling the 5,870-acre blaze in the Rogue River National Forest, just north of the California border.

“But sometimes, no matter how good we are, there’s still nothing we can do unless Mother Nature gives us a break,” he said.

And so it went Saturday throughout the Pacific Northwest, with firefighters pleased by the progress made over the last week and relieved that predictions of agitating thunderstorms, laced with lightning and winds, had generally failed to pan out.

“We had been braced for some bad weather, but it really hasn’t developed,” said George Lennon, a spokesman for the Pacific Northwest Incident Management Team in Portland, Ore. “In fact, we’re making some good progress today.”

The most precarious fire was burning a few miles from Leavenworth, Wash., where residents were advised to consider evacuation should “a worst-case scenario develop,” Lennon said. “But even if the winds changed directions and started blowing hard toward Leavenworth, the residents there would be looking at one or two days of good burning before they’d have to leave.”

In Northern Calfifornia, the Ponderosa fire near Weimar in Placer County had scorched more than 1,200 acres and crept dangerously close to dozens of homes. Another fire closed a popular swath of Modoc National Forest.

At the national wildfire coordination center in Boise, Idaho, spokeswoman Davida Carnahan said the prognosis is good. “The crews have been pretty much holding their own today,” she said.

The number of large, active fires burning in the West had dropped to 30 Saturday, the lowest number in days. It included nine in Oregon and eight in Washington.

“We’re still on guard,” Carnahan said. “A cold front is moving through the Northwest, with unstable winds promoting erratic fire behavior.”

The weekend’s isolated storms may ignite fires that won’t be discovered for days--after a lightning-singed tree or underbrush finally erupts and takes off with the wind.

Most of the large fires still burning were ignited by a swarm of dry thunderstorms in the Western states a week ago, launching a belated start to the summer fire season.

That a fire can quickly grow to thousands of acres, and burn for days if not weeks before being extinguished, is the nature of a beast that man has little control over, fire experts say.

“I can look at a 200-acre fire and just know it’s going to grow to 5,000 acres before we can stop it,” said Rob Kopack, a veteran firefighter working this summer at the government’s wildfire coordination center in Boise.

The reason: Once a fire develops a dangerous head--even with flames just a few feet high--it is too risky to place firefighters directly in its path. Instead, firefighters must play catch-up by building fire lines along its back side and extending them along both flanks of the blaze, hoping eventually to overtake it. The task is all the more daunting in steep, mountainous terrain, where fire moves easily but man is slowed.

The goal, which may take weeks to reach, is to eventually draw the firebreaks along the flanks closer together, eventually pinching off the head of the fire.

Along the way, firefighters might succeed in herding the fire in one direction or another to avoid homes, but only if the weather cooperates. Wind trumps man.

Help can come from the air, with helicopters dropping water and airplanes dumping fire retardant, which is orange to mark where it has been dropped.

But while aerial drops can reinforce firebreaks or extinguish small flare-ups, neither tactic is effective, Gilpin said, in directly attacking flames that are shooting 40 feet or higher.

If the fire is “blowin’ and goin’,” there’s simply no stopping it, and firefighters face that much more catch-up work. Fire bosses will frequently forfeit thousands of acres to the advancing fire and order firebreaks constructed well ahead of its path--and one or two backup firebreaks behind them.

But if a wind-driven fire ignites the tops of trees, setting them off like torches, firebrands can easily blow a half mile, over the firebreaks.

Even on a calm day, a large fire can send a column of smoke and embers 10,000 feet into the air; the hot material can drift over firefighters’ heads, igniting spot fires outside their fire lines.

Gilpin, one of the Oregon Department of Forestry’s most experienced commanders, said firefighting is nothing less than a war--except that no casualties are acceptable. Aircraft drop water instead of bombs, bulldozers replace tanks, infantrymen carry shovels instead of rifles, a command structure maps strategies and advance scouts report on the movement of the enemy, which is fire.

And just as the military has embraced technology, so have firefighters.

Gathering intelligence is key, Gilpin said. Firefighters are sent as close as they dare to the fire and mark their locations with global positioning satellites.

The plots are then recorded on topographical maps developed by the U.S. Geological Survey and then printed at the base camp and distributed to division leaders to aid their troops’ movements.

With input on the type of terrain, the weather and the type of vegetation fueling the fire, analysts in the base camps use computer modeling to predict where the fire will burn next.

Aircraft take infrared measurements that betray where the fire--perhaps shrouded in smoke or beneath the canopies of tall trees--is burning hottest.

All of this information is evaluated by fire bosses who determine where the firebreaks should be constructed. Depending on the amount of combustible material on the forest floor, breaks of several feet in width, or up to the width of a bulldozer blade, are cut into the earth, depriving the fire of fuel.

Under certain conditions, fuel breaks are created by setting small, manageable fires along the desired path, with firefighters on the ground keeping them in check. Helicopters can ignite the fires by dripping flammable gel from buckets. That strategy does not work, however, if the dripping, fiery goo lands in the tree canopies, igniting their crowns.

Enter the Ping-Pong balls.

They are filled with the same flammable gel and taken aloft by the helicopters. Moments before they are ejected like small bombs, they are injected with another chemical. After they are dropped through the trees and hit the forest floor, a delayed chemical reaction causes them to erupt as miniature fireballs.

But for all the technology, the outcome depends on when Mother Nature calms her winds, drops temperatures or delivers humidity, if not rain.

And then it is the hand crews who capitalize on the turn of the weather, draw in their flank lines and pinch off the yielding head of the fire, finally shrinking in size as it is choked from both sides.

“When the hand crews from both sides meet, and a crew boss radios in, ‘We’ve hooked the fire, we’ve got a line around it,’ there’s no greater sense of satisfaction,” Gilpin said.