During an emergency, weather officials in both the public and private sectors face a daunting challenge: not only must they get their message out quickly, but their message also must be accurate and provide specific information about a plan of action. Since 1994, the United States government has relied on the Emergency Alert System (EAS) to communicate these messages to the public. The EAS uses one-way analog communication channels like NOAA weather radio and television, plus television and radio broadcasts, to deliver emergency messages.

Technological advances have created opportunities for weather officials to communicate with their increasingly mobile stakeholders. For instance, sending short message service (SMS) text messages to individuals' cell phones has been championed by some as a viable alerting tool. However, four technological issues severely limit the effectiveness of weather officials' use of SMS technology. First, in general, SMS is limited to 93-160 characters of plain text per cell phone screen. Second, wireless networks do not deliver SMS messages in real time. This increases the chance that messages will build up in users' message queues, especially if individuals' cell phones are turned off. Third, SMS servers are susceptible to security breaches and “spoofing.” Fourth, sending large numbers of SMS messages simultaneously creates a burden on the wireless network. This was evident during the September 11 attack as well as the 2005 London bombings.

At first glance, weather officials' use of multimedia messaging service (MMS) to communicate complex information (using, for instance, an embedded graphic like a radar image), would be an improvement over sending such information by SMS. The primary problem here is the bandwidth required to deliver MMS messages. During a severe weather event, the mass distribution of MMS messages could exacerbate the network load issue already caused by SMS messages.

The emerging Cellular Broadcast Service (CBS) is designed to overcome the limits of the existing SMS network. CBS technology allows brief, authenticated text alerts to be sent to cell phones. There are two significant advantages to distributing warnings through CBS technology: (1) the messages do not negatively affect voice and SMS network traffic, and (2) the warnings can be targeted to all individuals who are within range of a specific cell tower. This second point is especially relevant to weather officials who, using this technology, will be able to deliver location-specific watch and warning messages to different stakeholder groups.

In 2006, Congress passed the Warning, Alert, and Response Network (WARN) Act that tasked the Department of Homeland Security (DHS) to upgrade the existing EAS to meet the communication needs of a mobile society. In 2008, the Federal Communications Commission (FCC), in collaboration with other government agencies including the National Weather Service (NWS), began developing the Personal Localized Alerting Network, or PLAN. Through PLAN, weather officials can deliver “imminent threat”-type messages (e.g., tornado warnings) to the public using CBS technology. To receive these messages, mobile users must have a special handset. Yet, only select high-end smartphones (like the latest iPhone) currently can receive such messages. In the future, though, all major wireless providers have agreed to make their consumer handsets compatible with PLAN's technical standards.

Moving forward, the different stakeholder groups who are developing PLAN's standards—stakeholders who include National Weather Service officials—face several challenges. First, the current version of PLAN only supports text-messaging alerts in English only. Second, PLAN's technical standards, by design, do not allow embedded hyperlinks to be included in the message. The concern is that once individuals receive a message, they will browse the Web from their smartphone to get more detailed information about the event. This, in turn, could overwhelm wireless providers' 3G and 4G networks. Third, as yet, the FCC only requires wireless providers to send text-based alerts that include no more than 90 characters. Thus, a significant problem with the current version of PLAN is how weather officials can include all the relevant message elements in 90 characters or less, and do so without adding a hyperlink to richer communication media like a radar image.

A broader issue around implementing PLAN, which was also evident with the EAS, is that PLAN relies principally on a one-way, “command and control” communication model to centralize coordination during emergencies. Increasingly, emergency response officials are leveraging peer-to-peer, ad-hoc networks (also called smart swarms and word-of-mouth meshes) and use social network sites like Facebook and Twitter to help distribute emergency messages. In the future, weather officials could use the GPS capabilities that are already built into individuals' mobile phones to send location-specific messages/maps, including evacuation routes, directly to these phones. Further, as Andy Bailey from the NWS has argued, by using a cell phone's built in camera, weather officials potentially could use augmented reality (AR) applications that superimpose real-time weather information (e.g., weather, radar, and current warnings) onto the phone's camera image. Delivering these maps, and creating AR applications, likely will require the increased bandwidth speed promised by wireless providers' 4G network. Regardless, these examples demonstrate how weather officials can use the power of social networks to help distribute severe weather messages.