ANZA, Calif. -

Riverside County firefighters stopped the spread of a fast-moving vegetation fire near the town of Anza that could threaten the Cleveland National Forest -- home to the San Jacinto State Park.

Spokeswoman Melody Hendrickson said crews were called to Cary Road and Tripp Flats Road to extinguish an outbuilding that had caught fire at 12:40 p.m. Friday. The flames quickly spread to the surrounding dry vegetation.

When you see news happen, send pictures and video to Newsline 3!

At 1:30 p.m., 25 acres had been scorched and one double-wide mobile home had been destroyed, Hendrickson said.

Forty-five minutes later, the fire had eaten 50 acres, and the California Highway Patrol officers arrived to close roads in the area to give the growing number of firefighters room and protect drivers from danger.

The intersections of Cary Road at Cave Rock and Cary Road at Bautista are closed, according to the CHP website.

At 2:50 p.m., the fire had grown to 75 acres and was nearing 100 acres fast.

They stopped the fire from spreading at 4 p.m., Hendrickson said.

An out house and a double-wide mobile home were consumed by the fire, but no one was hurt.

As crews work in the 91 degree heat, 11 mph winds and 20 mph gusts, they're also trying to find out how the fire started, she said.

Stay with KESQ.com and CBSLocal2.com for more on this developing story.