Assessing Risk Following a Wireless Emergency Alert: Are 90 Characters Enough?

In a relatively new initiative, homeland security and other emergency management officials use wireless cell technology to communicate Wireless Emergency Alert (WEA) messages to an increasingly mobile public. Severe weather warnings represent one type of WEA message that the public can receive on their cell phone. So far, officials have limited WEA messages to 90 characters of text and therefore have excluded information-rich weather graphics like warning polygons and radar images. The question remains if this lean messaging strategy effectively communicates the risk and severity of the storm. In the current study, the researchers created prototype WEA tornado warning messages equivalent to both popular mobile weather apps on the market and the National Weather Service's iNWS service to compare to typical WEA text-only warnings. The study therefore investigates WEA weather warning message effectiveness across one of four conditions: (1) WEA (text-only) alert; (2) WEA text+NWS warning polygon; (3) WEA text+radar image; and (4) WEA text+warning polygon+radar image. Participants were told they were driving through an unknown region of the US. The researchers asked participants to assess the perceived risk, perceived severity, and likelihood to contact a loved one for each message. The results indicate the decisions did not differ as a function of warning type. Also, the participants' times to make the three decisions were equivalent across all four types of messages.