The problem is, in a major event, even after the event, can leave cell towers destroyed, compromised, overloaded, grid goes down, lines down, generating plants down etc, etc. In a major event, computers, telephone landlines and cell phones are generally the first to go and some don't come back for a long time.
Bingo. After Katrina, I had no power for six weeks (yeah, I was lucky). After 10 days, I could get incoming calls on the land line. No cell service. No incoming cell service on my cell number anywhere, because cell switches in the 504 were down. People have no clue how hard it was.