Red Flag Fire Warning Reminds San Diegans Of Past October Wildfires

San Diego County is again under a National Weather Service red flag fire warning as Santa Ana winds combine with hot weather and dry conditions.

The warning, in effect from 2 a.m. Wednesday until 8 p.m. Thursday, comes at the same time of year that San Diego's most destructive wildfires have occurred. October is typically when vegetation reaches its driest point and strong Santa Ana winds blow.

During the Cedar fire in 2003, walls of flames driven by hurricane-strength winds roared through neighborhoods. The fire killed 15 people, scorched more than 2,200 homes and forced the evacuation of thousands.

Four years later, a similar catastrophic scene erupted when the Witch Creek, Harris, Poomacha, Horno/Ammo and Rice fires scorched 576 square miles of the county. Ten people died, 500,000 were evacuated and 1,600 homes burned.

“I saw things I’d never seen before,” said Cal Fire Battalion Chief Pete Scully, who has worked as a firefighter for 40 years. “I can honestly say it was the worst day of my career. Flames going horizontally. Not up, but just blowing straight across, a solid wall of flames. I saw rates of spread that I could not drive fast enough to keep up with."

Both 2003 and 2007 were exceptionally dry. Canyon slopes and hillsides were browned to a crisp, just like they are now, said Scully.

“The fuels are bad, and they’re getting worse,” Scully said.

Scully specializes in reducing hazardous vegetation that could fuel fires. His father was a firefighter, so is his son. Last week, he walked through Japatul Valley in the East County where critically dry vegetation is ripe for burning.

“You can see the buckwheat, you’ve got some dieback on the buckwheat,” he said, pointing at the grassy plant. “This is that chamise again that we were looking at, this portion here has completely died.”

He said the chamise shrub is a good indicator of the heavy toll of five years of drought. The plant can grow to about 10 feet tall, and has tiny needle-like leaves and white flowers that bloom in the spring. The die-off of the flowers at the tips of the plant is normal, but Scully said he's seeing more than that.

“When you see actual leaves start to die and we see things such as whole portions of the shrub dying, this tells us the shrub is very stressed and is now becoming dead fuel,” he said.

Dead fuel is extremely flammable because fire does not have to use energy to dry off living plants, or “live fuels,” he said.

“So if there’s moisture in this fuel, all of that moisture has to be driven out before it can actually get hot enough to burn,” he said.

Live fuels with enough moisture can slow a fire down, Scully said. But when Santa Ana winds push fire through dead vegetation it can quickly become an unstoppable force of nature.

“Under the right conditions with the right slope you could easily get 100-foot-tall flames coming off this brush,” Scully said.

National Weather Service

Most shrubs around the county — especially on south-facing hillsides — have dipped below critical moisture levels. Already dead are tens of thousands of oak trees decimated by beetles, and tall grasses that sprouted in spring.

“Most fires are going to start in either the grass or the fine dead fuels that you see at the base of this bush,” Scully said.

Then there’s topography. San Diego’s canyons and hills combined with its dry climate makes it one of the most dangerous fire regions in the country. A wind-driven fire can move approximately four times faster going up a 45-degree angle compared to flat land, Scully said.

“So therefore, more fuel is being consumed, the flame lengths get bigger,” Scully said. “As the flame lengths get bigger it generates more heat, which preheats farther ahead of itself, which causes the fire to burn more efficiently so it becomes sort of this snowball effect as it moves up slope.”

Steep hillsides also make firefighting difficult for ground crews carrying heavy hoses.

“We can’t use tractors or bulldozers on steep slopes,” Scully said. “Aircraft can’t get into the canyons as effectively because of updrafts, and you can't fly a big air tanker down through this canyon.”

Hundreds of thousands of acres across the county have burned over the last 13 years. Still, Scully said most of the county remains at high risk for fire. He urged people to clear clutter from their yards, remove flammable vegetation from around their property and evacuate if told to do so.

“They fail to understand how dangerous and how hot and just how fast these fires can burn,” he said.

U.S. Navy