In two decades of fighting fires from the sky, air tanker pilot Peter Bell had never seen anything like the vortex in the Southern California skies this week.

"There was a big spiral, like a tornado, that sucked all this dirt and garbage into the sky," he says.

Windshields on six tankers were cracked by the debris, and cockpits filled with smoke. Another pilot saw a 4-by-8 foot sheet of plywood sail past at 1,500 feet.

Thirty-five air tankers — and 86 helicopters — have been attacking flames since the wildfires started in Southern California on Oct. 21. Their key role has been to dump their $3,000 loads of retardant on the outskirts of the fires to help crews build firelines around the flames.

To many of the pilots, the fires that have ravaged Southern California this week are among the most intense they have ever had to fly through.

Usually, airtanker pilots are employed to douse small fires before they spread. Here, pilots are being forced to fly through narrow canyons, thick smoke and high winds. Earlier this week, the amount of wind-swept debris they were encountering prompted pilots to begin asking for reconnaissance planes to fly ahead of them on missions.

"People think we're daredevils, but we're not," said Bell, a pilot from Missoula, Mont., working under contract for the U.S. Forest Service (search). "All we do is practice safety, safety and safety."

In a 270,000-acre wildfire in San Diego County, the state's largest blaze, flames sent hot air into the atmosphere, while cooler air alongside the flames pushed down, creating a wind shear.

"It's like driving a car over a plowed field," said California Department of Forestry Capt. Ron Serabia.

Serabia and other pilots flying missions throughout Southern California said they were stunned by the damage caused by the blazes: "It looks like the surface of the moon. There's not a stick of wood."

"Have you ever seen pictures of Hiroshima? That's what it looks like," said tanker pilot Jim Cook.

The job has risks even during lesser fires.

Two pilots died earlier this month when an air tanker just like the one Bell flies crashed in the San Bernardino National Forest (search), where Bell has been working this week. It was the eighth air tanker crash in the United States in the past decade, according to the National Interagency Fire Center (search) in Boise, Idaho. Sixteen people have died.

Three crew members were killed in a June 2002 crash near Reno, Nev., when the wings fell off a 1957-model C-130A tanker as it dropped retardant. The next month, a wing snapped off a P4Y-2 air tanker near Estes Park, Colo., killing both crewmen. Those two types of tankers have been grounded by the Forest Service and Bureau of Land Management (search).

The nation's fleet of air tankers includes Orions, DC-4s, DC-6s, and DC-7s and P-2V Neptunes, owned and operated by private companies under contract with the Forest Service or state forestry departments.

Only about 12 tankers can fly around any single fire without creating gridlock or risking a collision, said Fred Batchelor of the California Forestry Department.

On Thursday, dense fog kept planes grounded most of the day in the San Bernardino region. On Wednesday, it was thick smoke that kept them down. Earlier in the week, 30 mph Santa Ana winds off the desert made it useless for them to even attempt dropping fire retardant.

The planes do not directly save homes. Pilots said their heavy load of retardant could do more damage to a house than a fire would.

At a Forest Service air tanker center in San Bernardino, where the planes make 25-minute dashes in and out of a blaze dozens of times a day, shaded bleachers have been set up for observers.

"They're big and they're loud," said David McCallum of Riverside, who stopped by to watch on Wednesday. "I love the concept of these operations, the work, the activity, what's involved. It's all very exciting."