If you are using ham, you'd likely need a repeater at that distance, especially if your terrain is hilly. If cell towers are down, it's quite possible (likely?) ham repeaters are also down. You could buy 2 ham radios as a plan B and see if they work. You'd want to talk to someone about the appropriate wattage (strength of signal) to buy and if they know about local repeaters (or google repeaters in your area). Handhelds would likely not have the juice. A car model might, and a home model likely would. But you're talking a few hundo at least.

I have 2 handhelds and one "portable" (car model). I bought them for emergency prep, but in the fires in SoCal relied on cell networks, wifi and twitter to communicate. I tried ham, too, but frankly twitter had better info faster.