An end-of-spring heat wave sent temperatures soaring into triple digits in Southern California, making conditions difficult for firefighters on two blazes.

A 12-acre fire wildfire erupted in Ventura at midday Thursday and moved uphill in brushlands.

Ventura County fire spokesman Bill Nash said more than 100 firefighters are on the lines, and one firefighter was been treated for heat exhaustion.

Firefighters are also battling a brush blaze in eastern San Diego County.