The teams left around 3 a.m. Monday. The Los Angeles Fire Department deployed 43 firefighters in total.
Fire officials said 12 firefighters were sent up north as part of command support, 23 will join the strike team at the "Rocky Fire" in the Lower Lake area north of San Francisco and eight firefighters from Beverly Hills, Culver City and Santa Monica will join the strike team at the "Six Rivers Fire" in the Six Rivers National Forest near Ruth Lake.
Firefighters from the CAL FIRE Riverside unit also traveled north to help.
CAL FIRE Riverside Unit joins forces to battle fires burning in Nor Cal. Rocky Fire: Credit, Div. Chief Steve Beach pic.twitter.com/f1udS7QfUl— CAL FIRE Riverside (@CALFIRERRU) August 3, 2015
Los Angeles City Fire Chief Ralph Terrazas said many local units want to help, but they need to be strategic and can't share as many firefighters as they like to because they need to be adequately staffed in the Southland.
It's not clear how long crews will stay up in Northern California.
Unfortunately scattered thunderstorms and gusty winds are expected to make things worse for firefighters and evacuees.
The Rocky Fire, which is the most stubborn blaze of the bunch, tripled in size over the weekend and charred some 93 square miles - that amounts to nearly twice the size of San Francisco. As of Monday morning, the fire was 12 percent contained. Nearly 3,000 firefighters were working tirelessly to contain the massive fire.
The Rocky Fire is now considered historic in size. As the fire burns north, there's a huge assault in the air and on the ground to stop it. Backfires are being set to head off the heart of the blaze and keep it away from a highway.
"There's so much energy and heat in the main body of the fire, and we don't want that energy and heat right at the roadside," said Steve Kaufmann with Cal Fire.
PHOTOS: Smoke from Lower Lake area wildfire seen for miles
PHOTOS: Crews battle Rocky Fire in three Northern California counties
Thousands have been evacuated from the path of the Rocky Fire, a massive wildfire that started burning near Clear Lake on Wednesday, July 29, 2015. The explosive fire is now burning in three Northern California counties -- Lake County, Colusa County, and Yuba County.
The blaze has already destroyed 24 homes, 26 outbuildings and is threatening another 6,300 homes, many of them ranches scattered in rural areas ranging from grasslands to steep hills.
Roughly 12,000 people have been ordered to evacuate as the military has called up two more C-130 firefighting planes from Colorado to join the large DC-10 tankers.
Closer to home, firefighters are battling a brush fire in the Los Padres National Forest. It broke out just after 1 p.m. Sunday north of Ojai near the Maricopa Highway. No structures are threatened.
More than 9,000 firefighters are battling around two dozen fires burning across California.
One firefighter was killed at the scene of a fire at the Modoc National Forest, 100 miles south of the Oregon border, and four other were burned in a blaze near Sacramento.
Gov. Jerry Brown has declared a state of emergency and will mobilize the National Guard if need be.
The Associated Press contributed to this report.