Those of you who know me know that I work with Amateur Radio (ham radio). If your loved ones in the affected areas know a ham, that person can transmit what we call "health and welfare" traffic and have it relayed to people outside the area; during Katrina, this was the only method available to get traffic in and out of the area after all the cell phone sites died.
Also, you can register with the Red Cross and their "safe and well" site at
https://disastersafe.redcross.org/default.aspx. If you have been affected by a disaster, this Web site provides a way for you to register yourself as "safe and well." From a list of standard messages, you can select those that you want to communicate to your family members, letting them know of your well-being.
If anyone has any questions on using Amateur Radio to contact friends and family, just pm me.