LOS ANGELES — The wildfires that raced across the hills of Southern California this week have tested the tough regulations California communities put in place to contain widespread destruction of homes in these seasonal fires.

But as the fires continued to roar out of control in some parts of the state, rules like requiring homeowners to clear flammable bush near their houses have proved to be of mixed success, fire officials said on Monday. While they can certainly help in slow-moving fires, they have proved no match to the high-wind fires that made this fire season in California so destructive.

“It helps in that it gives us defensible space,” said Ralph M. Terrazas, the chief of the Los Angeles Fire Department. “However, once the winds become high speed, the downwind embers can easily jump to the house and clear that defensible gap.”

The largest of the Southern California fires has burned through 230,500 acres, mostly in Ventura County, and is only 15 percent contained. More than 640 homes have been destroyed and 167 have been damaged, according to Israel Pinzon, a spokesman for Cal Fire. The high winds, which were expected to subside over the weekend, are now forecast to last through Tuesday.