CONCORD -- Gusty winds howled at more 60 mph in the canyons on Mount Diablo early Wednesday, triggering a red flag warning for all of the Bay Area except San Francisco and whipping of fears of wildfires.

Local firefighters warned residents to be vigilant.

"A concern of ours is that people have sort of moved on into winter," said Oakland fire Chief Robert Lipp.

And it appeared Lipps' concerns were well founded. Oakland Hills resident Mark Carstersen compared a red flag warning to the oft-ignored terrorism levels.

"It's (a red-flag warning) similiar to the terror alert level," said Oakland Hills resident Mark Carstersen. "It's something that increases the anxiety but there's not much you can directly do. So it's more of an awareness thing."

Oakland Fire Capt. Melinda Drayton said that three special fire units would be patrolling Skyline Boulevard and portions of Redwood Road on Wednesday to get a "bird's-eye" view of the hills and surrounding areas.

Firefighters will also be keeping an eye out for anyone involved in "high-risk fire activity" and will be giving advice to citizens on how to go about their daily activities when fire danger is high.

"We will have units meeting and greeting anyone engaged in activities that could lead to a fire," Drayton said. "Firefighters will be approaching people using gas-powered appliances like lawnmowers or weed whackers, tossing lit cigarettes or conducting illegal burns."

Drayton added that small fires started by homeless individuals living in the ravines around the hills have been smoldering in recent days and firefighters are paying special attention to those to make sure they don't reignite.

Meanwhile, the National Weather Service has extended the red flag warning until 10 a.m. Thursday for dangerous fire conditions across the hills of the Bay Area.

Dry and gusty offshore winds of up 35 mph with ridge-top gusts of more than 60 mph prompted the alert for hilly areas of Sonoma, Napa, Marin, Santa Clara and San Mateo counties, according to the weather service.

Hot temperatures, high winds and low humidity -- the relative humidty at Santa Rosa had dropped to 8 percent by noon Wednesday -- add up to what the weather service calls "explosive fire growth potential."

The warning has also prompted officials to shut Mount Tamalpais State Park north of the Panoramic Highway and to suspend all park use permits. No vehicles were permitted Wednesday on Pantoll Road or Ridgecrest Boulevard, according to the Marin County Fire Department.