If something major scale events happens (Katrina or earthquake scale kind of event) the local responding units will be incapacitated or totally flooded with high priority tasks everywhere. Even if you could get through to them they probably can't help you.

Cell phone text messages are much more likely to go through if you have a bad signal or the system is bogged down by everyone calling at the same time. Ask your recipient to confirm the transmission.

Another option is using SPOT or a similar system, using the PLB satellite system to send a primitive pre-defined "I'M OK, this is my position" kind of email/SMS to your relatives. That is probably one of the easiest, fail-safe options in an "all-out" earthquake scenario, but the messages doesn't convey anything but the fact that you're alive. Of course you'd want to check that the service does not rely on any physical installations in California...