The "phone Co." can block calls in the disaster area. So an out of area contact plan is a must. I've used mine before and for 2 or 3 days it was the only way to comunicate and it is a good way to get information also. After the Loma Prieta quake initially I coulndn't drive the 15 miles to my GF's place,or phone her, but my out of state contact was able to contact both of us.
When I could drive out there, I brought what was needed.
Dave