Camp Pendleton fire crews have extinguished one brush fire and are monitoring others that ignited on base Friday afternoon and left smoke and flames visible in Orange County.

Three brush fires began in a training area in the northern portion of the base around noon, while a fourth began several hours later in the southern portion of the base.

Camp Pendleton said Friday that it is extending its live-fire artillery training through Saturday.

The base has been conducting exercises all week and had been scheduled to end them at midnight Friday. But units will continue training in the Whiskey and Zulu impact areas until 2 a.m. Saturday, then resume from 5 a.m. to midnight Saturday, the base said.

Regimental live-fire artillery exercises involve about 25 howitzer 155mm cannons. Depending on atmospheric conditions, the explosions may be heard up to 50 miles away, the base said.

For more information, call 760-725-0357 or see Camp Pendleton’s noise advisories here.

The fires in the northern portion of the base were believed to have been sparked by training exercises. Marines were reportedly conducting live-fire artillery training in the area.

By Friday evening, the base firefighters contained and were mopping up the blaze in the southern portion of the base, which they referred to as the “river fire.” It reportedly burned about 6 acres before being brought under control.

Crews were expected to monitor the three smaller fires in the northern portion of the base overnight. It wasn’t immediately clear how many acres those smaller fires have burned.

Base officials said there is no threat to personnel or structures.

No injuries were reported.

Orange County Fire Authority officials said they had received numerous calls from South County residents who saw the flames and smoke.

Published: Sept. 14, 2012 Updated: Sept. 19, 2012 7:59 a.m. 

By SEAN EMERY / THE ORANGE COUNTY REGISTER

Contact the writer: 714-796-7939 or semery@ocregister.com