SAN MARCOS, Calif. (AP) — Winds haven’t reappeared in San Diego County wildfire areas and authorities say it’s a window of opportunity to make gains against flames that have scorched thousands of acres and destroyed homes.

Emergency officials also say Thursday morning that a significant number of firefighting aircraft are now available, including 22 military helicopters.

Ten of those are being used to battle a 6,000-acre blaze on the Marine Corps’ Camp Pendleton. Twelve others are available to the county, where the biggest concern is a blaze at San Marcos. That fire is now 800 acres and is 5 percent contained, and thousands remain evacuated.

Fires began erupting Tuesday amid high heat and gusty Santa Ana winds. Asked about the possibility of arson, Sheriff Bill Gore says he won’t prejudge the investigations.