The American Red Cross is the best-known voluntary agency active in disasters. Most people are familiar with their local chapter. When a disaster receives a presidential disaster declaration, the Red Cross and FEMA work together to help state governments and NGOs to plan & coordinate mass care and feeding programs.
Red Cross, Disaster Preparedness for Seniors. (32 pp)
Some additional resources, supplied by the Red Cross:
The Ready Rating program is an excellent way for houses of worship to assess their preparedness, then use the resources on the website to expand their capacity. It is free to join and free to use. I used it in my congregation and school to improve our preparedness significantly. Many houses of worship also have space that could be used as a Red Cross shelter. The Red Cross will inspect the facility to see if it meets needs, and when needed, will supply all materials and staff. It is also a great volunteer opportunity to take the training a become a staff worker at your shelter and others.