(Reuters) - More than 11,000 homes and businesses were ordered to evacuate on Wednesday and power was cut off to many residents as a wind-lashed wildfire roared out of control in San Diego County, authorities said.

The so-called Poinsettia Fire, which erupted shortly before 11 a.m. in the seaside California community of Carlsbad, some 25 miles north of San Diego, quickly became a top priority for crews battling flames across the region.

Approximately 11,627 homes and businesses in the Carlsbad area received the directive to evacuate ahead of the flames, San Diego County said on its emergency services Web page. Emergency shelters were set up at area schools and community centers.

Local television images showed what appeared to be a number of homes burning, and San Diego Gas and Electric reported that an estimated 2,000 residents in and around Carlsbad were without power.

Meanwhile, a second fire, called the Tomahawk, broke out on the Camp Pendleton Marine Base north of San Diego and had left more than 100 acres charred by mid-afternoon, prompting the evacuation of military housing and a naval weapons station.

The new fires erupted just hours after crews aided by diminished overnight winds made substantial headway against the so-called Bernardo Fire, which had forced thousands to flee their homes in and around San Diego for several hours in the afternoon and evening on Tuesday.

By daybreak on Wednesday, firefighters managed to establish containment lines around 25 percent of the Bernardo Fire's perimeter, with all evacuation orders lifted and area schools reopened, according to fire officials.

But since erupting late on Tuesday morning, the Bernardo has scorched more than 1,500 acres of brush, and officials said fire teams faced a potentially difficult second day.

"We're very worried about today," said Lee Swanson, a spokeswoman for San Diego Fire and Rescue. "We're looking at gusting winds to 50 miles per hour, humidity at 5 percent and temperatures reaching 100 degrees (Fahrenheit). Those are dangerous conditions."

The fires flared as California entered the height of wildfire season in the middle of one of the state's worst droughts on record, setting the stage for what fire officials fear could be a particularly intense and dangerous year.

California officials have kept staffing levels for wildland firefighters at elevated levels since last year because of the drought.

(Reporting by Marty Graham, Steve Gorman and Dan Whitcomb; Writing by Dan Whitcomb; Editing by Cynthia Johnston and Gunna Dickson)