Someone cut a major fiber line in New River back in 2015.
Internet disrupted throughout Northern Arizona, 911 wouldn't work from Northern Phoenix area to the Utah border.
All people had to do was call the non emergency numbers, and they would get through.
Our MDT's still worked (Verizon air cards), but dispatch networks did not.
Most people who call 911 don't have legit reasons to, so 911 going down is pretty much a non issue, more a blessing.
Jay