Where people don't have mobile phone access during an emergency, reach them by landline with voicemail messages or over the internet with informative emails. Thanks to the data you already have in your crisis contact list, you will know how to reach the most residents regardless of where they live. If a person has requested to be contacted by mobile device and you suspect that mobile is down, you can try another channel with the emergency notification system. By having all of this information ready, you will be able to reach the widest audience.