If there's smoke, there's a reason to call the firefighters.
A combination of gusty winds, low humidity and dry grasses -- cooked brown by summertime heat -- means a Red-Flag Warning is in effect for the Bay Area, where it's peak fire season.
The warning is in effect in areas 1,000 feet above sea level in the East Bay Hills, Contra Costa Hills and Diablo Range from 6 p.m. Thursday until 6 a.m. Saturday.
Mount Diablo, which burned last month in a wildfire, and Henry Coe State Park are also part of the warning.
Winds may gust at speeds of up to 45 mph, according to weather forecasters, which means a fueled fire can spread quickly.
Kristen Jensen knows exactly how real the threat of fire can be. The Morgan Fire on Mt. Diablo forced her family to evacuate three times as flames go dangerously close to their property.
The Jensens now have hoses placed around their home. They plan to be on extra alert as the Red-Flag warning is in effect.
Barbecuing in parks will be forbidden -- and fire officials stress the need to call 911 at the slightest hint of smoke.
"Don't wait for your neighbor to do it," fire spokesman Kent Kirby told the Contra Costa Times. "Call immediately."
Residents throughout the Bay Area are advised to lessen the fire risk by refraining from mowing dry grass, keeping vehicles off of dry grass, refraining from burning landscape debris such as leaves or branches and target shooting only in approved areas.
California Department of Forestry and Fire Protection officials said extreme fire conditions are expected throughout the state this week.