If LAFD is the primary responder in Bell Canyon area, and they do extensive mutual aid in Kagel Canyon and the Chatsworth county island area, I suppose there is a chance that some LAFD companies have a batch of VHF portable radios (since Ventura County FD and Los Angeles County FD use VHF portables AFAIK). Or does LAFD use their 800 Mhz portables, and dedicate 1 person to maintain face to face coordination with the County IC?
San Fernando Valley Fire Stations - Google Maps - this map shows the areas involved - LA County Sta 74 and 75 - first stations on the list
Nice map zerg! Now you need to expand it to cover the Angeles National Forest and the southern portion of L.A. County. You would want to include some of the adjacent stations of Orange, Ventura and San Bernardino Counties as well, as those stations often roll, via automatic aid dispatching, to calls in L.A. County. While you are at it you should put the stations of the other 87 cities in L.A. County as well. Many of those contract with L.A. County for fire protection so just doing the county would eliminate the scope of the workload.
Another interesting situation involving L.A. County is the municipality in Orange County that contracts with L.A. County Fire for fire protection. It is right on the border with L.A. County and is isolated from the areas the Orange County Fire Authority protects by adjacent cities that provide their own.
I can't think of any fire departments that have the complexity that the L.A. City and L.A. County fire departments have. High rise buildings (L.A. County not so much), a major world airport (LAX), oil refineries, manufacturing, a major world seaport and the most difficult wildland-urban fire workload in the country. Other cities, such as New York, have a greater complexity of high rise structures, but don't have the wildland component that these two departments have and I don't think New York has the oil refinery workload that L.A. County has. They may not have as much chemical manufacturing as L.A. does either. Some of these components exist in the same battalions in L.A. and certainly in the same divisions. A battalion chief may have to respond to more than one of these components in a single shift. This requires a broad knowledge and skill set that is hard for me to imagine.
L.A. County also is contracted by CDF to provide prevention and suppression for the SRA there. I've never heard of CDF having to take over the management of any fires in L.A. County as the fire department has lots of dozers, inmate fire crews and helicopters. They also have good management teams as well. Many of the county and SRA fires move up into the Angeles National Forest where the feds send in incident management teams, but many are large enough to consider major incidents where CDF only sends tankers, engine strike teams and inmate crews in a mutual aid mode.
Looking at this map and those L.A. County Fire Department stations along U.S. 101 reminds me of the largest of the incredible fire season of 1970 in California. This fire started on the south side of 101 and the ignition was viewed by firefighters in either 65's or 125's. Some people in a car threw out some burning debris. The station self dispatched and by the time they drove to the nearest freeway crossing and back to the point of origin the fire was already too big for initial attack. It burned down to the Pacific and then back into the Santa Susana Mountains, north toward Pyramid Lake and then eastward on the Angeles National Forest where it jumped over the 8 or more lane Interstate 5. This after making many unsuccessful attempts at stopping the fire at other major defensive points. I had a supervisor who was working at Oak Flat Station on the Angeles adjacent to I-5 at the time. I asked what they did when it crossed the I-5 and they said they just sort of followed the fire and got everyone out of the way because they knew they couldn't do much of anything else.