No-notice evacuations transpire when an incident, such as a terrorist attack, tsunami, tornado, or earthquake, occurs with limited to no warning (Zimmerman et al., 2007). Events range in scale from local to entire cities or regions of a country. Emergency response planning is usually entirely reactive because of limited planning. The size, location, nature of the incident and time of day are among the key factors affecting the complexity of No-notice evacuations (ibid). These factors impact how many people are affected by the evacuation and how quickly rst responders can evacuate personnel. Trust in warning messages is one of the most important factors for citizens in emergency evacuations (Glik, 2007; Paul, 2012). Glik also found along with trust, if citizens received detailed information about the severity of risk, they were more likely to evacuate in an orderly manner and respond to directions of emergency managers (Glik, 2007). Although rumors are spread using social media, Richards and Lewis (2011) found in the 2011 London Riot that rumors were often dispelled within two to three hours. Similar challenges exist with existing emergency reporting methods. For example, in 2011, police in Britain reported less than 25% of over 7.5 million calls were real emergencies (Boyle, 2012). In order to establishing trust in social media during emergencies, emergency managers and organizations should maintain a social media presence before events happen, thereby establishing credibility with other users prior to an emergency.