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Two wind-driven brush fires in Orange County, California, have burned more than 10,000 acres combined and forced at least 100,000 residents to evacuate from their homes.

The Silverado fire broke out in Irvine on Monday morning, and by evening it had scorched 7,200 acres. Orange County Fire Authority Chief Brian Fennessy told the Los Angeles Times that a 26-year-old firefighter and a 31-year-old firefighter both sustained second- and third-degree burns while battling the blaze, and are now intubated at a local hospital. "They're gravely injured," he said. "We're doing all we can for them."

On Monday evening, Southern California Edison told the state's Public Utilities Commission it is investigating whether its equipment may have sparked the Silverado fire. So far, no homes have been reported destroyed.

A second blaze, the Blue Ridge fire near Yorba Linda, has burned 3,000 acres and destroyed one home. The dry Santa Ana winds are fanning the flames, and gusts of up to 70 mph were recorded in Orange County on Monday. Relative humidity was at 5 percent, "which is bone-dry," National Weather Service meteorologist Dan Gregoria told the Times, and the dry air combined with high winds is "creating these critical fire conditions."