Nice. My wife and I are one different carriers purely for disaster purposes. I used to have a wifi router on a third as my travel/work-backup. This is a good step for major disasters.

The downside is that, in the event of large-scale power outages, it will only be so helpful. When I lived in the US, I rode out hurricane Ike in Houston and we had no cell service as the battery backups on the cell towers slowly expired. Some in 24 hours, the longest I think in 72.