A red flag which reads "fire weather" is flying outside the Moraga-Orinda Fire Department to warn residents of the danger.
In Oakland, firefighters are on patrol looking for potential fire threats. "We're worried about those winds this weekend, dry vegetation is growing as we get into summer," said Oakland battalion fire chief Dino Torres.
Joaquin Miller Park in the Oakland Hills, is closed this weekend as a precaution due to high fire danger.
In Pleasanton, many were coping with extreme heat at the Alameda County Fair where temperatures soared over 100 degrees. "We put on a ton of sunscreen before we got here, we're looking for shade and drinking water," said Pam Hurley.
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Fair officials urge patrons to take it easy. "We say every hour, take a break seek shade and drink some water. We have first aid on site and they can help if you need it," said Alameda County Fair spokesperson Angel Moore.
Moore says later in the day, five fair guests were treated for heat related illness.
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Cal Fire has brought on an additional fire-fighting helicopter and stationed it in Sonoma in response to the red flag warning for fire danger across much of northern California, fire officials said.
Cal Fire strategically placed a Blackhawk helicopter from PJ Helicopters at the Sonoma Air Attack Base, fire officials said.
A red flag warning has been issued for parts of the North Bay this weekend for high fire danger due to gusty winds, hot weather and low humidity, according to a statement from the Sonoma County Sheriff's Office.
RELATED: Scorching Bay Area temps; Fire danger still high
The warning runs from 11 a.m. today through 8 p.m. Sunday. Cal Fire also brought on an additional helicopter stationed at
Chico Air Attack, and a tanker stationed at McClellan Air Tanker Base in response to the red flag warning, fire officials said.
Area residents are advised to avoid lawn work, driving on grass, campfires or fireworks. Lit cigarettes should always be disposed of safely.
Elevations over 1,000 feet in the affected area are at the greatest risk.
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Bay City News contributed to this story.