How Individuals Process NWS Weather Warning Messages on Their Cell Phones

U.S. government officials are focusing their attention on how to deliver timely and effective warning information to the public, especially given the devastating weather-related events that have occurred in recent years. With the increase of cell phones (and in particular, web-capable smartphones), weather warnings sent through various cellular technologies represent one way for officials to quickly notify an increasingly mobile public. Cellular technology innovations also make it possible for officials to broadcast information-rich media like graphics to cell phones. Whether warning messages must include such "rich'' media to be effective remains an open question. The current study investigates the effectiveness of National Weather Service (NWS) warning messages sent either in plain text or in text that includes a radar image of the storm. The research protocol was modeled after the interactive National Weather Service (iNWS) messaging service currently available to NWS core partners. In the study, participants read full-text NWS warnings of tornadoes or flash floods that either did or did not include a radar image of the storm. The researchers timed participants' ability to decide if a critical town was in the warning area, and then probed their understanding of the message content. Results show that participants' decision times to the town question did not differ between the graphic and no-graphic conditions. None of the other message content measures differed as a function of message condition. The results have potential implications for the federal government's new Wireless Emergency Alert (WEA) system, which, as yet, is limited to text-only warnings.