A trucker with a CB can send critical information 40 or 50 miles on the 11m band on a good day. Legally they are limited to 5w output. Even with a yagi, this is going to be tough.
HAMs (Skilled QRPers) on the other hand regularly communicate to other continents with 5w of power. Your typical 100-150W HF rig is going to be able to communicate anywhere in the world--or worst case, anywhere in the continental US. Some HAMs are also trained in emergency communications and/or formal traffic handling (to verify the accuracy of messages.) HAMs can use modes like SSTV (Slow Scan TV) to send an image of a piece of damaged infrastructure or a damaged building so engineers or rescuers can come in properly prepared. APRS mode is designed to update a real-time map of mobile and stationary transmitters using GPS. Information like this can also be critical in a disaster information. Rescuers won't have to guess where to look to find an injured person, etc... HAM radio is much more than Morse Code (CW) and people talking to each other like on CBs.