Individuals may not receive messages via usual sources. Social media such as Facebook, LinkedIn, Twitter and social networking groups have been useful in the notification, information dissemination, safe notices, and reunification.

A survey of the literature and of social media sites to determine what possibilities of notification, information exchange, marked safe, and reunification information that can be helpful in disasters.

Social media is useful during all phases of a disaster: pre-disaster notification, information dissemination during disasters, and safe notices/reunification post-disaster

Social media is internet-based and requires a device that needs power. There is widespread internet access to various forms of social media, such as email, various broadcast sources, and social networking sites. Social media may provide pre-disaster warnings (weather alert app, reverse 911), evacuation/sheltering information, blocked routes, open gas stations, stores with supplies, hotels/motels with rooms, and shelter locations. Social networking groups were full of messages informing others they could shelter someone fleeing the California wildfires and recent hurricanes. Volunteers can be alerted and responses collected via social media groups. Social media may reach individuals earlier than official announcements, although sometimes accuracy may be in question. Rumor and malignant information source as well as inaccurate information are possible and may need to be managed. Separation is common during disasters. Knowing if their loved ones are safe and well, then reunifying is critical, especially for the vulnerable: children/infants, elderly, and disabled. Reunification systems need safeguards for vulnerable individuals who may be exploited or abused during disasters. In previous disasters (Hurricanes Maria, Mark, and others; California wildfires), when usual communication was nonfunctional due to downed power lines or damaged/destroyed substations; social media was deluged with individuals giving names and identifying information for family and others and asking whether anyone has seen or heard from them.