Firefighters on Wednesday began to assert control over wildfires that have burned through nearly 500,000 acres and displaced half a million residents over four days in Southern California.

While many fires continued to burn Wednesday, especially east of San Diego, and officials warned that weather changes could reinvigorate waning flames, lower temperatures and abating winds have helped to greatly reduce the threat.

Some fire officials were congratulating themselves on having avoided extensive loss of life, even setting dates for when the biggest fires might be brought under control.

But the second-guessing that comes with any natural disaster was already beginning. Questions were being raised about how the firefighting has been coordinated, how resources have been deployed, and whether Southern California has gotten smarter after the 2003 fires that scorched the region and its psyche, or if it has just gotten lucky.

The recent fires have sharpened questions about the costs of protecting the increasing numbers of people who live in remote and fire-susceptible areas forced new examination of the tension between the need for local emergency services and the willingness to pay for them.

San Diego County, the largest county in California without a fire department, relies on a hodgepodge of local departments that are often low on funds.