CASTIAC, Calif.—A wildfire near Castaic on Saturday has led to the closure of a part of a major freeway in Southern California, officials told local media. The fire, known as the Route Fire, reached 392 acres, or a little more than half a square mile, as of 6:28 p.m. and forced the shutdown of a section of Interstate 5, a Los Angeles National Forest spokesperson told KTLA-TV. KTLA reported that the Route Fire is threatening structures, according to the Los Angeles County Sheriff’s Department Santa Clarita Valley station. The fire was uncontained as of 6:30 p.m., authorities said. Elsewhere in California, thunderstorms that dropped light rain gave some breathing room to crews struggling to quench the state’s massive wildfires but lightning sparked several new blazes in the drought-stricken north, fire officials said. The storms that rolled through Thursday night into Friday were followed by weekend forecasts of clear weather and …