Los Angeles County Fire Department personnel responded to reports of a brush fire near the southbound side of State Route 14, south of Agua Dulce Canyon Road, just after noon, according to Supervisor Leslie Lua.

Firefighters on the scene reported a half-acre blaze upon their initial arrival, moving uphill in southwest winds of about 20 mph, Lua said. By 12:50 p.m., the fire had grown to 4 acres.

“Quebec 2 is dipping out of Castaic Lake,” she added, referring to the Super Scooper, a water-dropping aircraft.

The fire was reportedly started by a vehicle fire spreading from the freeway to nearby brush, according to Franklin Lopez, a spokesman for the Fire Department.

A SigAlert was announced shortly after 12:30 p.m. due to officials needing to close the far right two lanes to deal with the growing blaze. The Agua Dulce on-ramp heading onto the southbound side of the 14 was also closed due to the fire response.

“(The SigAlert) should be clearing up in about an hour,” said Officer Stephen Brandt of the CHP Traffic Management Office.

This is a breaking news story and will be updated as more information becomes available.