The weekend before nine wildfires erupted in the San Diego area, scores of state firefighters were sent along with engines and aircraft to the region — knowing that the forecast of a heat wave and gusty winds was setting the stage for a tinderbox.

The positioning of crews was among several steps fire officials say they have been fine-tuning since 2003 when the San Diego area experienced one of the worst infernos in California's history. Communications between firefighting agencies has improved, residents are notified more quickly when to evacuate, and more aircraft are available to dump water on fast-moving flames.

A flare-up Thursday prompted 18,400 new evacuation notices in and around San Marcos, a north San Diego, suburb, and served as a reminder of how quickly conditions can turn. But with cooler temperatures forecast, there was an overwhelming sense that far more damage could have been inflicted on a region of more than 3 million people.

This week's unseasonably early wildfires have driven tens of thousands from their homes and shut down schools and amusement parks, including Legoland, which reopened Thursday. Flames have charred more than 15 square miles and caused more than $20 million in damage, burning at least eight houses, an 18-unit apartment complex and two businesses. Firefighters found a badly burned body Thursday in a transient camp in Carlsbad — the first apparent fatality — and a Camp Pendleton Fire Department firefighter was treated for heat exhaustion while battling a square-mile blaze on the Marine base.

San Diego County had some of the strongest Santa Ana winds Wednesday, with gusts reaching up to 50 mph, which may have set conditions for fires to be easily ignited, just as they were in 2003. The 2003 Cedar Fire scorched more than 437 square miles, nearly 3,000 buildings — including more than 2,000 homes — and killed 15 people before being contained.

The tragedy led to California creating one of the world's most robust firefighting efforts, which resulted in the smooth evacuation of thousands this week and crews able to save hundreds of homes from being consumed by the fast-moving wildfires, said Battalion Chief Nick Schuler of the California Department of Forestry and Fire Protection.

Before another devastating wave of fires swept the San Diego region in 2007, the city and county introduced a 'reverse 911' system of automated calls to homes and businesses. Previously, evacuations were accomplished by going door to door or driving down the streets with loudspeakers.

Upgrades at dispatch centers have allowed firefighting agencies to share resources far more quickly by computer, a contrast to 2003 when agencies had to pick up the phone to move engines around, said David Allen, division chief for the state firefighting agency.

There is also a stronger relationship between the state firefighting agency and the military, which had 22 aircraft fighting the fires Thursday.

Those procedures are expected to be tested further as drought-plagued California heads into the summer months of what is expected to be one of its busiest firefighting seasons yet.

Jeff Bowman, the former city of San Diego fire chief who was on duty for the 2003 firestorm, said the outcome of this week's blazes was what everybody hopes for, but several factors worked in firefighters' favor that weren't in place in 2003 and 2007.