Three local disasters in the last decade has proven to me that wireless can not be relied on during an emergency. As during all three cellular was useless, SMS was a crap-shoot, the authorities were even on local radio stations begging people to not use their cellular phones to free up the towers so emergency personal could use them.
A wide spread power outage even took down ALL the cellular services. I could not get a Verizon signal nor could I even get a roaming signal. You think the phone companies would have UPS and generators on the cellular towers, think again.
Though all of this my POTS line worked flawlessly.
20+ years 0% outages