Before the Santiago fire started in the hills northeast of Irvine, the Orange County fire department already had been hobbled.

Its fire engines were staffed below national standards, it had fewer firefighters per capita than neighboring counties, and its army of men and women ready to fight the blaze may have been weakened by changes in the county's volunteer firefighter program.

Making matters worse, local crews and equipment had been sent to the Malibu fire, as had reinforcements from the state. Aircraft remained grounded because of the wind and bureaucratic obstacles.

"We're out there with a handful of crews trying to stop this big fire, and all we could do was just put out spot fires," said Chip Prather, chief of the Orange County Fire Authority. "It would have been great to have the cavalry come in, but there were several fires burning, and it was taking time for the resources to get here."

As a result, the blaze that began last Sunday punched through the county's defenses, destroying at least 16 homes, threatening more than 3,000 and forcing tens of thousands of residents to evacuate.

Orange County's problems with the Santiago fire illustrate a recurrent pattern in much of Southern California -- county fire departments that find themselves ill-equipped to handle a major blaze.

Sometimes, help from the state or neighboring counties comes to the rescue. Other times, a fire is so huge that no reasonable amount of people and equipment likely will suffice.

In some fires, however, lack of resources makes a difference. Those blazes are the ones that highlight a region's shortages. The Santiago fire appears to have been one such blaze -- a winnable brush-fire battle that grew into a prolonged, expensive and dangerous war.

Like most departments in the region, the Orange County Fire Authority was ready for trouble. Forecasts called for humidity in the single digits and hot Santa Ana winds roaring in from the desert.

Prather put 30 extra crews on duty, roughly 100 firefighters. They added to the typical staffing of about 70 crews. He was paying firefighters overtime to have engines staffed and ready to go.

The size of those crews was one way that Orange County fell below the national standard. Most of the county's engines were staffed with three people. Four per engine is the voluntary minimum standard from the National Fire Protection Assn., a private organization that writes fire safety guidelines.

Crews with three firefighters work more slowly than larger crews, according to a study by the Insurance Services Organization, a national group that evaluates fire departments.

"When you lose one person on the crew, you're sacrificing safety," said Afrack Vargas, a spokesman for the California State Firefighters' Assn. "You're sacrificing another set of eyes. You're sacrificing another strong back to help in the incident. It makes a difficult situation that much more difficult."

State rules require that two firefighters be present as backup for every two that enter a burning building. With three on an engine, that's impossible.

Orange County fire officials say they can't afford larger crews.

"We have a budget, and there's only so much we can do within that budget," said Capt. Stephen Miller, the Fire Authority's spokesman.

In 2005, the Orange County firefighters union pushed for a local ballot measure that would have provided fire departments a larger share of revenue from Proposition 172, a half-cent sales tax passed by voters in 1993 to raise money for public safety agencies statewide. The bulk of the funding went to police.

The local measure, which would have added tens of millions of dollars to fire department budgets, ran into opposition from the county Board of Supervisors and ultimately failed at the polls.

Orange County, the sixth-wealthiest county in the state, has an annual firefighting budget of about $260 million. The Fire Authority has roughly one firefighter for every 1,100 people in the county's coverage area. But that figure climbs dramatically -- one firefighter for every 1,800 residents -- if only full-time, professional firefighters are counted.