May I suggest to my Anons the use of Meshtastic devices. California's cellular infrastructure hasn't ever been tested by a real earthquake. Each tower has a microwave antenna connecting it to the rest of the towers nearby. Should the alignment of the antenna's be off by 10cm, the entire system crashed. Earthquakes move antennas. The system will be of no use for weeks.
California did something stupid and lazy. They allowed one cell tower to be a master cell tower the rest get trunked into landlines from that tower. All up and down the valley it will be misaligned for months.
Meshtastic will get you through those periods of no comms. Plus, you got me, now I won't tell you my elevation, but if you're a huge Revelation fan, you'll know it by heart.
Mesh up your life, you will not regret it.