50 MHz means 6 meters and above -- basically, nothing that has any regularly occurring usable propagation modes.
Moon-bounce and ham-sats occur regularly enough to be useful. Granted, hamsat passes are so short-duration and so sought-after that they aren't useful for much more than bragging rights, and moon-bounce is too technically challenging to be useful for routine communications, but they are there.
RF-based repeater networks on the 2m (~146MHz) and 70cm (~440MHz) bands are common in the United States. They offer communications over hundreds of miles without using anything but the airwaves. Ditto some mountaintop- and very-high-tower-based repeaters. A single repeater that covers a 50-mile-or-more radius is more convenient and therefore frequently more useful in an emergency than an HF-based NVIS net (NVIS is a way of setting up your HF antenna for "short range" communications of about a few hundred miles or less. Unlike typical antenna setups, they do not have any "skip", which is very useful in an emergency).
In situations where the Internet infrastructure is still up (which is almost always except during emergencies, and frequently during emergencies as well), repeaters that link to the Internet can provide worldwide communication on any band.